close

Вход

Забыли?

вход по аккаунту

?

The prenatal growth of the guinea-pig.

код для вставкиСкачать
Resumen por el autor, R. L. Draper.
El crecimiento prenatal del conejillo de indias.
El conejillo de indias es muy susceptible a la acci6n del frio y
a 10s cambios bruscos de temperatura y dieta. Estos agentes
son frecuentemente la causa de la muerte de 10s individuos
adultos y tambibn de abortos. La temperatura mas conveniente
para estos animales es la de 60" a 70" F. El periodo de celo no
puede determinarse fitcilmente mediante la observaci6n externa,
durando cinco horas en un caso extremo. La fecundidad del
conejillo de indias se ha exagerado. Solamente un cuarenta por
ciento de las hembras criadas quedaron preiiadas. Los embriones de menos de diez y siete dias no pudieron pesarse satisfactoriamente. Las variaciones de peso de 10s embriones j6venes
son relativamente mayores que las de 10s fetos pertenecientes a
10s estados ulteriores de la gestaci6n. El crecimiento es r&pido
desde el d6cimo-quinto dia hasta el vigksimo-quinto dia de la
gestacih. Decrece rtipidamente a1 principio y despu6s mas
despacio durante el resto del periodo. El embri6n no aumenta
en longitud con la misma intensidad con que aumenta de peso
desde el d6cinioquinto hasta 10s sesenta y cuatro dias. El
fluido amni6tico y las membranas mantienen, relativamente, la
misma relaci6n con el crecimiento del embrih, aumentando mas
rhpidamente a1 principio y despu6s mas despacio desde 10s veinte
y nueve, y treinta y dos dias, respectivamente.
Translation by Jod F. Sonidee
Carnegie Institution of Washington
AUTHOR'S ABBTRACF OF THIB PAPER 1 8 8 0 ~ ~
BY THE BlBLlOGRAPHlC SERVICE, YIAY
24
T H E PRENATAL GROWTH OF T H E GUINEA-PIG
R. L. DRAPER
Department of Anatomy of the Stanford University Medical School
FIVE CHARTS
In the beginning of these experiments the animals were kept
under outdoor conditions similar to those to which they were
accustomed. They were sheltered from the wind, but not from
the cold or changes in weather, and fed on alfalfa. Diarrhoea,
which generally ended in death, followed and those that were
pregnant aborted. Convulsions were noted in a few cases, followed soon by death and abortion. A number of others aborted
without any apparent cause.
At necropsy the intestinal tract appeared to be normal in some,
while in others the intestines were inflamed and distended with
gas. Fresh green vegetables were then substituted for some of
the dry feed and the animals protected from the cold. The
sick ones immediately recovered and no further abortions occurred. Hence cold was probably the cause of the trouble,
although the guinea-pig is very susceptible to changes in diet
and seems to succumb to the slightest disorders of the intestinal
tract. However, abortions occurred also later.
Lantz ('13) also found that susceptibility to disease is closely
related to the quality and quantity of food eaten. Improper,
irregular, and deficient feeding is common cause of inflammation
of the stomach and bowels, from which losses among the animals
may be very great. In my experience the guinea-pig does best
when it is kept at a temperature of from 50" to 70°F. However,
Lantz found that the guinea-pig does best when the temperature
is not allowed to fall below 65°F. The pig survives a chill very
badly and recovers very slowly. It is upset by irregular feedings
369
3 70
R. L. DRAPER
and must have plenty to eat. When they are well fed they stand
the cold fairly well, but nevertheless do poorly. Sudden changes
of temperature have an ill effect. 1 have found that the young
also are very sensitive to cold, for they died when the temperature dropped from GO" to 58°F. Pregnant females almost always
aborted when chilled even when digestive disturbances were
absent. Too much food, 011 several occasions, also seemed to be
a cause for abortions.
It may be of some interest to record t8hattJhe pig may go for
a long period of time without water if given plenty of green
stuff, and nevertheless do very well. I have let them go for
six months without any water except what was obtained from
green food, such as lettuce, carrots, cabbage, etc.
I n order to keep track of the age of the embryo, the female,
after copulation, was placed in a cage by herself or with one pregnant pig that was easily distinguishable. Every step to eliminate any source of error was taken. The cage was tagged, giving
a description of the pig and the hour and date of copulation.
The pigs were never changed from one cage to another.
On an appointed day the pig was weighed and then killed with
illuminating gas. The uterus was exposed and severed from its
connections, using care to free the uterine wall of any excess of
surrounding tissue. The oviducts were cut across at the junction
with the uterus (a point easily recognized by a slight constriction
at the point of junction). The uterus was then separated from
the vagina and the vaginal wall removed. The weight of the
uterus was then taken before it was opened, and the embryos
removed in a definite order. The ova were more easily removed
when the uterine wall was incised over the placental site, which
was readily recognized by an area lighter than the surrounding
uterine tissue and by its firmness. The very small ova were
easily detached from the uterine wall by means of a camel-hair
brush, weighed and opened and the embryos removed. The
cord was cut about 3 mm. from its fetal attachment after being
tied to prevent the loss of a varying amount of blood. The
superfluous fluid was removed with blotting-paper and the
THE PRENATAL GROWTH OF THE GUINEA PIG
371
embryos weighed on a chemical balance as soon as taken from
the membranes t o prevent any considerable loss in weight by
evaporation. An attempt was made to treat the embryos as
nearly alike as possible to prevent errors in loss of weight.
A watch crystal of known weight was used as a receptacle and
thoroughly dried and cleaned before and after each weighing.
The embryos too large to be weighed on a chemical balance were
weighed on a torsion balance accurate to 0.1 gram.
The length was taken with a caliper, a number of readings
being taken of each specimen and the average used, to exclude
as much error as possible. All the measurements and weighings
were carefully checked and tabulated at once and embryos and
placentae preserved in 10 per cent formalin and labeled as to
weight and age.
It is recognized that there is a constant error in weighing such
small object? by the loss of unequal amounts of fluid or by unequal amounts of fluid clinging to the surface. The smaller the
embryo the relatively greater will the error be. In measuring
the length of young embryos a source of error lies in the changes
in posture and in the delicacy of the tiss-ie. I-Tence it is advisable
to harden the embryos in formalin before taking measurements.
This method likewise is subject to criticism because formalin
swells young tissue, but in embryos during the latter part of
gestation this source of error would be considerably less.
The observations taken of the weights and lengths were recorded after the following form:
Weight of foetus and unopened
Number of pig
membranes beginning disDate of coitus
tally in the right and left
Date of death
Weight of pig
horn
Weight of uterus and contents Weight of membranes and fluid
Weight of empty uterus
Weight of membranes alone
Weight of foetus alone
No. of foetuses
Right
Length of foetus
Left
Obviously, the only accurate method of obtaining data of the
Frenatal growth of the guinea-pig is to weigh the embryo. Read
3i L
R. L. DRAPER.
('13) obtained his observations on the prenatal growth by estimating the weight of the guinea-pig embryo from weights of
the mother on succeeding days. This method is obviously
inaccurate for, as ,Minot ('91) pointed out, the digestive tract
with a particularly wide caecum always contains a considerable
amount of ingested food, the bladder containing a greater or
less amount of urine, and sickness all introduce great fluctuations.
Another source of error is the difficulty of controlling the act
of defecation and urination before each weighing. Since the
early embryo weighs but a few milligrams, while other things
may and do cause a variation in grams, the value of Read's
method in determining the weight of the embryo is at once
evident.
In obtaining the data for this paper, the age of the embryo
was calculated from the day of copulation, gnd the female killed
a definite number of days following, although this does not
necessarily assume that conception follows within twenty-four
hours after copulation. Von Hansen ('76), in studying the
descent of the ovum, also made use of copulation in age determination and found that ovulation takes place from six and
one-half to nine and one-half hours following coitus. Minot
('91) observed that when copulation took place in rut the fertilization took place within twenty-four hours. It would seem then
that it is safe to assume that conception follows within twentyfour hours after copulation and that the latter age less one day
lies within a reasonable error of the true age of the embryo.
In calculating the ages of the embryos it became necessary
to know when the females became pregnant. Assuming that
the ovum was impregnated within a comparatively short time
after copulation, it became necessary to know when coitus took
place in order t o determine the age of the embryo. Hence the
female was tried each night and morning, by putting the male
in the same cage for a short period of time. The male approached
the female promptly and if she was in heat coitus followed at
once. If not, she never would submit later, but kicked the male
and uttered complaining noises. Occasionally a female was noted
to assume the manner of a male, uttering a purring sound and
THE PRENATAL GROWTH O F THE GUINEA PIG
373
walking about the cage in a strutting manner, but I saw a female
attempting to mount another female when in heat only on a
few occasions. The female does not always object to being
mounted by the male, but will not assume a position necessary
for copulation unless in heat. Others resist vigorously at first,
but submit to mounting if the male persists. Such submission
was only noted a few times, however.
If in rut the female will react when stroked lightly over the
hips, by assuming the position for copulation. This confirms
Loeb and Lathrop (’14), who found that in “Animals kept under
normal conditions the period of heat occurs approximately every
fifteen to nineteen days. When females are kept together in
a large pen, some will be seen sitting quiet, some eating a little
or walking about, making a small sociable, clucking noise. If
one moves occasionally, rather majestically among the rest,
making a low, purring noise similar to the noise of the male, she
is probably in heat; if not, she soon will be. In some cases a
female guinea-pig may reach a state of excitement in which she
assumes the manners of a male and attempts copulation with
another pig which happens to be in heat. She as well as the
second guinea-pig that allows her to attempt the r61e of the male,
will almost always be found ready for copulation. When one
or very few females are kept in a small cage and have become
relatively tame, those in heat when tickled along the flanks and
hips will react to the touch of the finger, assuming the position
for copulation. This sign, however, is of no value when the
animals are timid.”
It occurred to me that it might be of some value to know how
long a female stayed in heat, and five hours was the longest
duration observed. Some refused the male in three hours. One
objected in twenty minutes after copulation. Just how long
she was in heat before copulation was not determined however,
but it was less than fifteen hours in any case.‘ A vigorous male
After the compilation of the d a t a here presented, which were obtained in
1915-16, I learned t h a t Stockard and Papanicolaou (’17) concluded t h a t heat in
the guinea-pig lasts about twenty-four hours and t h a t t h e external appearances
of the vulva are not absolutely reliable. George, in unpublished observations,
374
R. L. DRAPER
will copulate many times in a few minutes, but he becomes
exhausted after a number of acts and will not mount again for
some time, even if put in with a fresh female. Since the male
is generally not very active for twelve hours following copulation,
three males were kept and used on alternate days only.
The guinea-pig was found to breed in greater numbers during
the spring months from February to June. The greater number
of copulations took place in April and the greater number of
pregnancies also quite naturally took place during this month.
During the autumn months the greater number of copulations
occurred in Kovember, but the total number of animals bred
was only 9s. Of this number 48 were killed and found pregnant.
Four of the 98 aborted. Five.of the pregnancies mere bloody
moles, and 41 pigs failed to become pregnant. That is, in 40
per cent of the number in which copulation occurred, the pigs
failed t o become pregnant. Hence, it would seem that the
fecundity of the guinea-pig is not as great as is generally supposed.
This confirms the statement of Lantz ('13) that the fecundity of
the guinea-pig has been greatly exaggerated.2 The guinea has
but two mammae and her period of gestation varies from sixtythree to seventy days. A female in her breeding prime may
be expected t o raise about twelve to fifteen young each year.
It is of some interest to note that of 145 embryos obtained
from 48 pigs, 76 were found in the left horn and 69 in the right.
The average number of foetuses per pregnancy was practically
3. Five embryos were the greatest number found in a pregnant
uterus and two the least. Minot ('11) noted that the number
of young was 1 t o 8 in a litter, 1, 2, 3, and 4 occurring most
frequently. The most frequent combination in my series was
came t o the conclusion, however, t h a t careful inspection of t h e vulva was sufficient in thirty cases observed by him, and t h a t since twelve out of thirty-six
pigs did not mate in thirty-four days, although females were tried twice diurnally, the oestrus cycle must often be longer than sixteen days or t h e period of
heat less than twenty-four hours, George felt inclined t o the latter conclusion,
because among other things several pigs mated after more t h a n sixteen days.
* A large series of cases would seem t o be required for reliable conclusions
regarding this matter, for out of a series of thirty pigs, George found only one
t h a t failed t o become pregnant upon the first mating.
THE PRENATAL GROWTH OF THE GUINEA PIG
375
two embryos in one horn and one in the other. Two were found
in one horn about as frequently as in the other. Pregnancy
occurred nine times in one horn alone. In pregnancies where
there was a single embryo in one horn and two or more in the
other, the single embryo was found to weigh more than the other
embryos in 80 per cent of the cases.
The embryo in a ten-day ovum still was so small that it was
impossible to open the membranes and isolate the embryonic
disc from them even with the aid of a lens under water. The
measurements of the three ova of this age were 6.5 nim. x 3
mm.; 6.8 mm. x 4.5 mm., and 6.5 mm. x 4.5 mm. Two elevenday ova were removed from the uterus and weighed. One ovum
was opened and something which was taken to be the embryo
was recovered. This, with about an equal amount of gelatinous
material, was weighed. The embryo appeared to be 2 mm. long.
The membranes of a fourteen-day ovum were also opened in
water under a dissecting microscope, and a white streak, apparently the embryo, seen; but an attempt to isolate it, failed. It
was closely associated with a very delicate amnion, and the
estimated length was 2.5 mni. A fifteen-day ovum was isolated
with difficulty and the weight of the embryo estimated to be
only about 1.5 mgm.; but an ovum of seventeen days was of
sufficient size, so that the embryo could be isolated with considerable care. Since they lie in fluid, the error in weighing such
small embryos is necessarily very great, considering that a drop
of water weighs 50 mgm.
If the data so obtained are accurate and sufficient in number
for each day, then any point on the curve plotted from the data
obtained should represent the median weight of the embryo for
that age. For instance, an embryo of forty days weighs 10
grams, according to the curve, and this corresponds to the actual
weighings. The curve shown on chart 1 conveys the impression
that the embryo grows faster during the later part of pregnancy;
but this, of course, is not true, for a curve plotted from the weights
and ages of the embryos represents only the relation of the weight
t o age and of the weights to each other or the actual increase
376
R. L. DRAPER
in growth from day to day, but not the rate of growth which is
indicated on chart 2.
From this chart it is obvious that it is impossible to represent
graphically on a chart the weight of the early embryos for the
reason that the increase in weight per day is so small in relation
Chart 1 shows the relation of t h e age t o t h e weight in the guinea-pig embryo
computed from table 1. Age in days is represented on t h e abscissa, 2.5 mm.
representing one day, and weight of the embryo is given in grams on t h e ordinate,
2.5 mm. representing 1 gram. Each dot represents the actual weight of t h e
embryo.
to the age. The circles representing the weights fall nearly on
a straight line until the twenty-eighth day is reached, when there
is a gradual rise. This is explained by the fact that the weight
T H E PRENATAL GROWTH O F T H E GUINEA P I G
377
of the embryo from day to day is not great enough in relation
to the age and our means of measurements to produce a rise
in the curve. The overlapping of the circles in the first. part
of the curve is clearly due to the extremely small weights. The
variation between the weights of the very early embryos is
relatively greater than that of the older ones. This is partly
Chart 2 shows a curve representing the percentage increase in weights per
day. Age in days is given on the abscissa, 5 mm. representing one day, percentage increase on the ordinate, 1 mm. representing 1 per rent. The curve is
coniputed from data in table 9.
due to the fact that there is more chance for error in weighing
small specimens, although some of the embryos in the same litter
varied as much as 100 mgm. This is not apparent from the
chart. The weights falling far outside the curve may be explained by the variation in the growth or by some error in obser-
378
R. L. DRAPER
vation. The percentage daily increase in growth represents the
actual rate at which an embryo grows from one twenty-four-hour
period t80the next; for the weight at the beginning of a twentyfour-hour period subtracted from that at, the end of the period
is t,he increase in the twenty-four hours, or the daily increment,
and from this the rate of growth can be computed. The curve
of the daily percentage increase in weight, chart 2, shows a tre-
Chart 3 shows the relation between t h e weight of the embryo and the weight
of the membranes. Weight in grams on t h e ordinate, 10 mm. equaling 1 gram,
age in days on the abscissa, 2.5 mm. equaling one day. Weight of the membranes taken from table 1. E ach individual weight represented by a circle.
mendous increase in the rate of growth in the early stages of
development as compared t o the curve showing the increase in
weight. At the end of the seventeenth day the daily percentage
increase is 200 per cent, but by the twentieth day it drops to
20 per cent. This is followed by a rise to 35 per cent, and then
there is a gradual decline t o 10 per cent at the end of the sixtyfourth day. It is evident that the rate of growth would gradually
THE PR ENATAL GR OWTH O F THE G U I N E A P I G
379
decrease, and the curve would reach the base line when the
guinea-pig reached its full growth following birth. Just how to
explain the first rise in chart 2 is not clear. The curve beg 11s
with 100 per cent on the fifteenth day and rises to 200 per cent
on the seventeenth day; but this is not what one would expect.
Chart 4 shows the relation between the age and the length of the embryo.
Length in millimeters is given on the ordinate and age in days on the abscissa,
5 mm. equaling one day. The d a t a were taken from table 1, each circle representing the actual length of the embryo. This curve represents the actual increase in the length of the embryo, t h e individual lengths being represented by
circles.
Chart 5 shows the daily percentage increase in length computed from the
d a t a in table 3. The daily percentage increase in length is given on the ordinate,
I nim. equaling I per cent and age in days on the abscissae. 5 mm. equaling one
day .
T E E ANATOMICAL RECORD, VOL.
18. N O . 4
350
R. L. DRdPER
It may be due to the very few weights or to errors of observation
since we are dealing with such small weights.
The curve of the percentage increase in length, chart 5, is a
smoother curve than that of the percentage increase in weight;
the daily percentage increase being more uniform. It would
seem that the embryo in its early stages of growth does not increase in length at the same rate as it does in weight. The
daily increase in length on the seventeenth day is only 18 as
compared to 200 per cent in the daily percentage increase in
weight. It begins at a daily increase of 23 per cent on the fifteent8hday, and follows a gradual decrease to 1 per cent on the
sixty-fourth day.
In comparing the relation between the membranes and the
embryos of corresponding ages shown on chart 3, it will be noted
that during the first month the weight of the membranes is greater
than that of the embryos. (The term ‘membranes’ is used here
to include the placenta and the membranes.) Between the
thirty-second and thirty-third days they are equal, and after
that the embryos gain rapidly in weight, while the membranes
gain slowly. Between the twenty-fifth and the fourty-f ourth
day the curve shows a more rapid increase in the growth of the
membranes than following this time. Probably this period of
rapid increase is an expression of nutritional demand on the part
of the embryo. The-growth of the membranes is not in proportion to the increase in weight of the embryo, for when they
have reached sufficient size to meet the demand of the embryo,
there is no further need for their rapid continued growth. Froin
this chart it would appear that the greater difference occurs
among the individual weights during the latter part of gestation.
This may be accounted for by the larger individual weights and
the large scale of the chart. The table shows that the same variation occurs throughout the term of growth. It is probable
that the size of the placenta may exert some influence upon the
rate of growth of the embryo. The smaller placenta necessarily
furnishes less surface for nutritional interchange on account of
its small uterine attachment.
The average amount of amniotic fluid taken from each ovum,
as tabulated in table 1, shows that it holds the same relation
THE PRENATAL GROWTH O F THE GUINEA PIG
381
to the embryo as does the membranes, and is greater than the
weight of the embryo up to the twenty-ninth day. From the
twenty-ninth t o the thirty-second day it equals the weight of
the embryo, after which it increases slowly to the fourty-fourth
day and remains about the same for t,he rest of the gestation
period. The amount of fluid and the weight of the membranes
are equal on the thirty-fifth day and remain approximately the
same t o the sixty-fourt'h day.
CONCLUSIONS
The guinea-pig is very susceptible to cold and to sudden
changes in temperature and diet. These things frequently are
the cause for the losses among the pigs and for abortions.
A temperature ranging from 60" to 70°F. mas found the most
suitable.
R u t was found difficult to determine by external observations
only and five hours the longest period of heat noted.
The fecundity of the guinea has been exaggerated. Only
40 per cent of the number bred became pregnant.
Embryos under seventeen days could not be weighed satisfactorily.
Variations between the weights of early embryos are relatively
greater than those from the later part of gestation.
Growth occurs rapidly from the fifteenth t o the twenty-fifth
day. It decreases rapidly at first and then more slowly for the
rest of the period.
The embryo does not increase in length at the same rate as
it does in weight from the fifteenth to the sixty-fourth day.
The amniotic fluid and the membranes maintain, relatively,
the same relation to the growth of the embryo, increasing more
rapidly at first and then more slowly after the twenty-ninth and
thirty-second days, respectively.
It is a special pleasure to thank Professor Rleyer for suggesting
and outlining the subject for investigation, for his continued
interest, and for revision of the manuscript.
382
R. L. DRAPER
BIBLIOGRAPHY
LANTZ,DAVID 1913 The raising of the guinea-pig. Farmer’s Bulletin 52.5.
United States Department of Agriculture.
READ,J. MARION 1913 The intra uterine growth cycle of the guinea-pig.
Arch. fur Entwickelungsmechanik, B. 35.
MINOT,C. S. 1891 Senescence and rejuvenation. Journal of Physiology,
vol. 12.
LOEB, LEO, and LATHROP,A. E. 1914 The correlation between the cyclic
changes in the uterus and t h e ovaries, in t h e guinea-pig. Biol. Bull.,
vol. 27.
VON HANSEN,
V. 1876 Beobachtungen iiber die Befruchtung und Entwickelung
des Kaninchens und Meerschweinchens. Zeitwhrift ffir Anatomie und
Entwicklungsgeschichte, Bd. 1.
STOCKARD,
CHARLESR., and PAPANICOLAOU,
GEORGEN. 1917 The existence
of a typical oestrus cycle in the guinea-pig: with a study of its histological and physiological changes. Am. Jour. of Anat., vol. 22,
pp. 225-283, and nine plates.
1917 The existence of a typical oestrus cycle in the guinea-pig and its
histology. Anat. Rec., vol. 11, pp. 411-412.
1917 A rhythmical ‘heat period’ in the guinea-pig. Science, N. S.,
vol. 46, pp. 42, 44.
383
T H E PRENATAL GROWTH O F T H E GUINEA PIG
TABLE 1
Gives the age of the emhryos and the observations tabulated i n the order taken. T h e
individual weights and lengths OJ ths einbryos and the memhranes are listed in the
order of their removal from:the uterus. The number of weights after the age represents the total number of embryos at this age. From this fable the curve of the
median averages for weight and length are plotted. The small weights obtained
for the ages of thirty-two and forty-si.x days probably are errors in observation
or due to a mistake as to the day o/ copulation
AGE I N
DAY8
10
11
14
15
17
19
20
21
22
23
24
26
27
28
29
30
31
32
33
34
35
37
37
39
41
43
44
46
47
48
49
50
N U M B E R OF OVA
1.560
2.307
2.809
2.868
3.763
3.903
5.923
4.613
9.350
10.553
10.%3
11.675
11.435
9.620
12.010
15.593
47.450
37.830
26.038
42.853
53.403
71.900
51.400
78.983
56.290
74.500
83.200
97.220
97.220
63.400
111.700
95.000
80.530
201.500
1.229
1.773
1.675
1.260
1.805
2.410
1.623
1.762
2.000
2.448
2.874
2.660
2.878
1.318
3.230
2.670
4.443
7.090
4.390
4.455
6.450
4.5<%
6.883
10.360
7.966
8.740
10,600
7.400
8.700
10.700
12.810
7.000
7.200
8.500
6.770
11.122
3
3
2
2
2
0
4
3
2
5
5
0
3
3
2
2
3
3
4
3
3
4
4
4
3
4
2
3
3
3
3
1
3
2
4
4
COMBINED WEIQBT
OF MELIBR.iNE8 A N D
CONTEKTY
0.154
0.425
0.992
1.467
1.830
3.950
4.513
3.360
7.517
6.911
7.831
7.821
7.803
4.090
8.770
10.153
19.966
3s. 500
20.939
26.950
36.710
44.223
56.610
38.389
69.733
44.340
62.800
71.990
85.OOo
81.700
27.500
102.900
87.500
73.632
186.511
384
R. L. DRAPER
TABLE I-Continued
COMBINED WEIGHT
.4GE I N
DIYS
WEIGHT O F UTERUS
51
52
53
161.500
119.040
5.5
194.500
279.100
213.330
13.500
11.950
17.100
12.800
17.600
18.370
153.500
190.750
140.600
200.900
158.950
205.700
6.800
12.220
11.200
15.650
9.550
12.000
AND CONTENT8
56
57
59
59
61
62
64
WEIGHT O F UTERUS
10
11
14
15
17
19
20
21
22
23
24
26
27
28
29
30
31
32
33
34
35
OF MEMBR.\NES A N D
CONTENTS
I
D"Yu
NUMBER O F OVA
3
2
0
4
3
0
5
2
3
2
2
2
2
147.OOO
106.110
179.100
189.905
302.000
138.950
177.460
124.900
189.OGO
148.800
203. OOO
WEIGHT OF I N D I V I D U A L
I
Average weight
of ova i n grams
Ova in grams
0.066
0.1416
0.506
0.779
0.957
0.007
0.140
0.386
0.658
0.873
0.0810
0.1442
1.418
1.589
1.990
1.800
1.383
1,285
1.264
1.370
1.920
1.473
1.690
1.660
2.310
3.008
1.310
4.780
3.895
7.482
9.920
7.208
8.450
8.982
11.1630
2.653
2.558
2.780
3.990
1.760
6.484
10.200
6.603
9.550
9.225
11.560
2.045
1.308
0.074
0.141
0.446
0.723
0.915
0.000
1.464
1.543
1.732
1.364
1.383
2.858
2.235
4.528
6.000
10.740
7.128
8.950
8.855
10.7200
10.7800
7.640
9.648
1.879
1.362
2.607
2.600
2.050
4.380
3.394
6.655
9.620
6.979
8.732
9.188
11.050
385
T H E PRENATAL GROWTH O F T H E GUINEA PIG
TARLE I-Confinucd
WEIGFIT OF I N D I T ' l D l j l L
AGE IN
DATS
iverage weight
)f ova in grams
Ova i n grams
37
13.650
l4.9SO
39
12.153
17.235
13.103
15.465
25.520
21.400
23.000
27.500
25.490
41
46
47
48
49
33.700
45.000
19.078
18.820
19.400
24.200
27.000
28.510
27.500
35.200
42.500
18.513
50
47.808
45.973
51
52
53
55
4s.000
52.390
50.500
53.720
47.600
41. i 0 0
66 .SO0
60.000
74.500
64.350
50.800
87.900
73.300
95 .€I00
5.5.000
64.450
66.950
74.100
86.200
75.500
108.000
43
4
56
57
59
61
62
64
13.7900
14.49OO
13.1330
17.9080
19.1250
2". 0000
22.0000
24.7000
35.0000
29.6700
14.220
12.796
17.433
21.530
23.630
28.330
27.900
27.500
34.300
43.750
34.000
17.753
18.255
46.253
46.478
-18.500
61.00
18.650
46.629
49.000
53.050
39.000
53,640
50.800
64.465
44.520
64.930
62.000
G4.000
58.400
68.470
59.150
62.450
87.000
74.400
101.500
46.15
AQE IN
NUNBER
OF
WEIGET OF ENBRYOB
DAYB
EMBRYOS
11
14
0.0018
15
17
19
20
21
22
23
24
0.0015
0.005
0.035
0.109
0.131
0.217
0.178
0.299
1
0
1
2
0.006
1
0.105
0.148
0.252
0.265
0.432
0.087
0.110
0.210
0.233
0.412
0.1240
0.225
0.209
0.127
3
5
4
0.234
5
3
AVERAGE
VEIGHT I N
GRAM8
0.005
0.035
0.100
0.177
0.223
0.224
0.381
386
R. L. DRAPER
TABLE 1-Continued
A G E IN
26
27
28
29
30
31
31
32
33
34
35
37
37
39
41
43
44
44
46
47
48
49
50
51
52
53
55
55
56
57
59
59
61
61
62
64
0.493
0.673
0.210
1.290
1.427
2.463
4.660
2.693
5.000
3.819
4.568
7.010
5.253
9.343.
12.000
13.400
18.000
15.490
8.000
20.070
31.000
11.160
36.058
37.000
40.800
41.800
38.400
50.580
57.420
54.000
60.950
57.800
81.620
43.000
64.500
74.500
0.543
0.573
0.710
1.075
0.117
1.940
4.920
2.590
4.450
3.835
4.665
7.360
6.023
8.250
12.400
13.800
18.700
17.070
8.200
23.200
27.700
10.190
29.903
41.000
43.480
41.600
31.970
52.700
49.370
49.000
56.050
58.770
78.100
62.600
65.500
93.200
0.665
0.751
0.390
1.450
2.160
4.890
:’.760
4.350
3.697
4.593
6.840
5.943
9.908
12.000
14.000
18.500
18.520
2.970
4.500
4.010
4.638
10.052
13.490
9.931
34.048
37.500
10.260
35.150
43.400
31.900
46.140
55.020
54.000
38.400
40.900
50.300
54.000
40.950
13.870
55.000
3
3
3
2
3
3
4
3
4
4
4
3
3
4
5
3
3
3
1
2
2
4
4
3
2
4
4
4
3
5
2
3
2
2
2
2
NUMBER
A G E IN
DAY8
11
14
15
17
19
UMBER OF
:MBRYOB
W EIGHT OF EMBRYOS
DAYS
LENGTE OF EMBRYOS IN MILLIMETERS
4.250
5.000
OF
EMBRYO8
2
1
.YERAGE
‘ElQAT I N
GRAM8
0.567
0.666
0.436
1.182
1.438
2.187
4.820
2.640
4.575
3.848
4.616
7.040
5.740
9.388
12.906
13.733
18.400
17.360
8.100
21.950
29.350
10.385
33.790
38.500
42.950
41.300
37.090
50.000
55.900
53.000
58.500
52.500
79.860
52.800
65.000
83.850
A Y ER A D E
ZNGTR I N
MILLIMETERS
4.250
5.000
THE PRENATAL GROWTH OF THE GUINEA PIG
3 7
TABLE 1-Conlinued
NUMBER
AGE IN
DATS
20
21
2'2
23
21
26
27
28
29
30
31
31
32
33
34
35
37
37
39
41
43
44
44
46
47
48
49
50
51
52
53
55
55
56
57
59
59
61
61
62
61
LENGTH O F EMBRYOS I N MILLIYETERS
EMBRYOS
9.250
12.000
12.250
9.700
14.500
15.200
18.500
00.000
21.500
22.700
29.500
37.000
32.000
31.500
34.000
40. OM)
48.0ll0
43.000
52.500
51.500
65.000
70.500
61.500
69.500
75.000
84.500
57.000
74.000
82.500
87.000
82.500
so.000
91.000
102.000
87.000
94.000
98.Ooo
114.000
86.500
65.000
83.850
9.250
12.000
13.000
9.500
10.050
17.030
is.oao
23.500
22.750
26.000
31.000
29,000
32.500
35.000
40.050
46.Ooo
45.500
50.000
52.500
6 2 .600
70.000
63.000
69.500
72.500
82.000
56.000
79.000
79.500
9.000
12.500
12.250
10.000
13.000
17.500
1s 000
27.000
34.000
30.000
31.000
34.000
39.700
44.000
44,000
51.000
52.500
61.590
70.000
6l.000
12.000
12.000
9.200
12.200
10.200
29.500
4
32.000
36.000
40.050
46.000
4
4
55.000
54.000
74.000
86 000
53.000
83.000
so.000
4
SO.500
80.500
s5.000
94.500
93.000
85.000
76.500
95.000
88.000
3
2
4
4
4
3
5
2
3
2
2
2
2
71.000
91.oco
99.000
113.000
54.500
ss.000
102.500
4
3
4
5
3
3
3
2
3
2
4
55.000
54.500
94.Ooo
82.200
78.000
93. oco
99.000
81.000
3
5
4
5
3
3
3
0
2
2
3
4
3
S6.ooO
90.000
102.500
s4.000
VT.H.kOE
ENGTH I N
MILLIME T E R S
9.1rx
12,100
12.375
9.701)
12.GO0
16.500
1s.100
22.500
22.300
27.500
33.600
30.300
32.500
3.1.700
40.100
46.000
44.100
51.700
53.400
63.000
70.300
62.800
69.500
72.800
83.200
55.000
79.000
82.500
90.500
82.500
79. 800
91.000
95. 500
87.200
94.000
95.300
113.700
85.500
89.000
102.500
388
R. L. DRAPER
TABLE l--Concl~ded
I
ACE IN
DAYS
15
17
19
20
21
22
23
24
26
27
28
29
30
31
31
32
33
34
35
37
37
39
41
43
44
44
46
47
48
49
50
51
52
53
55
55
56
57
59
59
61
61
62
64
NUMBER WEIGHT
OF
OBBERVA
TIOAB
W E I G E T S OF M E M B R A N E S A D N E X A
0.569
0.718
0.590
0.657
0.910
0.690
0.985
0.697
0.739
0.890
0.935
0.773
0.760
1.042
1.112
1.451
1.332
1.438 1.328
1.785
1.380
1.795
2.060
1.067
1.280
2.830
3.013
3.150
3.120
2.253
2.768
4.350
3.950
5.390
2.668
3.710
3.493
3.930
3.450
3.963 3.953
3.345
4.283
5.700
5.200
4.800
5.200
5.000
4.500
5.130
4.510
4.400
5.500
5.200 ' 6.300
9.000
9.000
4.128
4.293
5.998
6.020
6.500 i 7.000
6.770
7.510
5.670
6.000
5.970
5.500
8.230
7.690
6.490
6.970
5.700
5.500
4.800
4.700
5.050
6.980
5.000
5.920
6.000 ' 6.400
6.600
6.700
7.200
9.550
1
~
0.738
1.260
1.040
0.715
1.123
1.542
1.283
1.740
1.945
2.660
5.420
2.435
4.100
2.733
3.343
3.580
4.013
4.225
5.200
5.200
5.500
5.410
1.150
0.935
0.750
0.800
2.870
4.000
2.933
3.359
3.790
5.095
8.240
3.970
5.748
7.560
4.220
4.858
6.110
5.100
6 230
6.050
6.000
4.930
6.500
8.320
4.220
0.985
6.300
4.340
2
2
1
3
5
4
5
3
3
3
3
2
3
3
4
3
4
4
4
4
3
4
5
3
2
3
2
2
2
4
4
3
2
4
4
4
3
5
2
3
2
2
2
2
'
01
0.633
0,910
0.804
0.924
0.947
0.763
1,092
1.435
1.346
1.100
1.977
1.430
2.814
3.560
2.485
4.100
3.428
3.430
3.690
3.976
4.312
5.810
5.060
5.000
5.010
4.900
5.750
9.000
4.150
5.656
7.000
7.140
5.877
5.790
7.830
6.500
5.600
4.750
5.280
6.200
5.460
6.650
8.350
-I
AVERIGE
WEIGHT O F
AMNIOTIC
FLClD I N
~ n . 4 ~ 8
PER OVUM
0.560
0.445
0.704
0.373
0.000
0.605
0.598
0.516
1.121
0.326
0.654
1.204
1.854
0.057
1.920
3.004
3.490
3.080
3.700
2.814
4.837
4.930
5.540
14.000
6.600
5.400
4.115
7.183
4.500
2,040
0.000
1,640
7.100
0.000
0.000
5.270
1.370
4.190
9.400
2.750
9.300
389
THE PRENATAL GROWTH OF THE GUINEA PIG
T4BLE 2
Shous thc rnedzan iocight, the daily increase and 111.. percentage tncrease per day.
T h e average weight for each d a y f r o m thejifteenth to fhe sixty-fourth d a y toas ascertained (column 1 1 ) f r o m the curtie (chart 1 ) . T h c dally increase was next
coniputcd by subtractzng the weight o n one d a y f r o m that twenty-four hours later
(colimia 1 1 ) T h e percentage incrcase per d a y z s the relation between the daily
increase and the weight at lke beginnin! if the twenty-four-hour interval
A G E I N DAYS
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
- 4 V ER A G E W E I G R T I N
GRAlrlS
0.0015
0.0022
0.0050
0.0150
0.0350
0.0800
0.1400
0.2150
0.2950
0.3800
0.4700
0.5700
0.7000
o.sso0
1.1000
1.5000
2.0000
2.6000
3.3000
4.0800
4.9000
5.7500
6.6500
7.6500
8.8000
10.1Ooo
11.5000
13.1000
14.8000
16.6000
18.5000
20.5000
22.7000
25.0000
27.4000
DAILY INCREdSE I N
GRAMS
0.0007
0.0028
0.0100
0.0200
0.0450
0.0600
0.0750
0. 0800
0.0850
0.0900
0.1000
0.1300
0.1800
0.3200
0.4000
0.5000
0.6000
0.7000
0.7500
0,8200
0.8500
0.9OOO
1.0000
1.1500
1
1.4000
1,6000
1.7000
1.8000
1,9000
2 . m
2.2000
2.3000
2.4000
.m
PERCENTAGE D A I L Y
I N C R E A S E IN WEIGHT
47.00
127.00
200.00
133.00
128.50
75.00
53.50
37.20
28.80
23.70
21.30
22.80
25.70
25.00
36.40
33.30
30.00
26.90
23.60
20.05
17.35
15.65
15.05
15.05
14.76
13.85
13.90
13.00
12.15
11.45
10.80
10.72
10.14
9.06
R . L. DRAPER
TABLE 2-Continued
h G E IN D A Y S
50
51
52
53
54
55
56
57
58
59
GO
61
G2
G3
63
AVERAGE WEIGHT I N
GR.4MR
29.9000
32.5000
35.2000
39.0000
40.oooO
43.9000
47.1000
50.4000
53.9000
57.GOO0
61.6000
GG ,0000
71.0000
77.0000
5-1.'0000
D.4ILY I N C R E I S E IN
GRAMS
2.5000
2.6000
2.7000
2.8000
2.9000
3.0000
3.2000
3.3000
3.5000
3.TOO0
4.0000
4.-1000
5.0000
tj.0000
7.0000
PERCENTAGE DAILY
INCRE.4SE I N WEIGHT
9.13
8.70
8.31
7.95
7.M
7.33
7.25
7.02
6.94
6.86
6.94
7.10
7.60
8.50
9.10
391
THE PRENATAL GROWTH OF T H E GUINEA PIG
TABLE 3
S h o u s tho average length i n millimeters, actual increase in length per d a y and the
percenloge increase i n length. T h e average length for each d a y f r o m the fourteenth to the sixty-fourth d a y was ascertained from the median curve o n length
(chart 4 ) . T h e daily increase i n length and the percentage, increase were computed in the same manncr as the daily increase and the percentage incrcase in
table 2
AGE IN D A Y S
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
AVERAGE LENGTH I N
MILLIMETERS
2.6
3.2
3.8
4.5
5.4
6.4
7.7
s.9
10.1
11.5
13.0
14.8
16.7
18.8
21 .o
23.0
25.5
28.1
30.0
33.0
36.0
39.0
41.7
44.3
47.5
50.4
53.3
56.3
59.0
62.0
65.0
67.5
69.8
72.2
74.5
76.7
78.8
ACTUAL INCREASE IN
,ENOTR I N NILLIMETERI
PER D A Y
0.6
0.6
0.7
0.9
1.0
1.3
1.2
1.2
1.4
1.5
1.8
1.9
2.2
2.1
2.0
2.5
2.5
2.2
2.8
3.0
3.0
2.7
2.6
3.2
2.9
2.9
3.0
2.7
3.0
3.0
2.5
2.3
2.4
2.3
2.2
2.1
PERCENTAGE DAILY
INCREASE I N LENGTE
23.0
18.7
18.1
20.0
17.1
20.3
15.5
13.5
13.8
13.9
13.9
12.8
13.1
11.1
9.5
10.9
9.8
7.7
9.3
8.8
8.3
6.8
6.2
7.2
6.1
5.7
5.6
4.7
5.0
4.6
3.8
3.5
3.4
3.3
2.9
2.7
R. L. DRAPER
TABLE 3-Cunliii1rcd
A G E IN D A Y S
AVERAGELENGTHIN
MILLIMETERS
51
52
53
54
55
56
57
58
59
GO
61
62
63
80.9
82.5
84.2
86.0
87.8
89.3
90.7
92.2
93.5
94.9
96.5
97.7
99.0
64
100.0
.4CTUAL I N C R E . \ S & I N
aENGTH I X MILLIMETERS
PER DAY
2.1
1.6
1.7
1.8
1.8
1.5
1.4
1.4
1.3
1.4
I .6
1.3
1.3
1.0
P ERC E MT AG E D A l I Z
INCREISE IN LENGTH
2.6
1.9
2.0
2.1
2.0
1.7
1.5
1.5
1.4
1.5
1.6
1.3
1.2
1.0
Документ
Категория
Без категории
Просмотров
0
Размер файла
1 197 Кб
Теги
guinea, growth, prenatal, pig
1/--страниц
Пожаловаться на содержимое документа