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Physiology of the fetus by William Frederick Windle. 1940. Size 6┬╝ ├Ч 9┬╝ inches. Pages xiii + 249. 27 tables and 70 figures. Index. Cloth. Price $4.50. W. B. Saunders and Company Philadelphia and London

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PHYSIOLOGY OF THE FETUS, by William Frederick Windle.
1940. Size 6+ X 9+ inches. Pages xiii 249. 27 tables and 70 figures.
Index. Cloth. Price, $4.50. W. B. Saunders and Company, Philadelphia and London.
Dr. Windle’s book dealing with the physiological problems which
present themselves in the study of prenatal development will prove
a most welcome addition to the working library of both physiologists
and embryologists. During recent years investigators in all branches
of Anatomy have been pushing out beyond their old limits of descriptive morphology with increasingly critical efforts toward functional correlation and interpretation. The rapid progress occurring
concurrently in biological chemistry and physiology has been a great
stimulus to such work. In this trend mammalian embryology has
been somewhat of a laggard, partly because much of the morphological foundation so necessary t o an intelligent undertaking of
functional studies was still wanting, and partly on account of the
many technical difficulties inherent in making properly controlled
physiological studies on organisms with an intra-uterine habitat.
Dr. Windle’s book comes a t a n opportune time for the embryologist
in that his accumulating knowledge of the structure of growing
embryos is rapidly becoming adequate as a secure foundation for
superimposed studies utilizing the newer methods of chemistry and
physiology. To the physiologist the book should prove stimulating
from a different angle. Much of the earlier work of physiologists
who have strayed casually into prenatal fields has been less valuable
than it might have been had they taken more careful account of the
rapidly changing morphology exhibited by all animals in their
intra-uterine development. One is tempted to paraphrase to the
effect that too often “to them an embryo was an embryo and nothing
more.” The subtle age changes so characteristic of embryological
material have been loosely dealt with, or even as blandly ignored as
if embryology were still being interpreted according to medieval
doctrines of preformation. Windle’s careful assessment of age
changes and species differences in interpreting the significance of
experimental data should be as constructive €or the physiologist as
his discussions of newer physiological and chemical methods are
for the morphologically niinded embryologist.
In the introductory chapter essential fetal-maternal relations are
outlined and there is a discussion of the special problems involved
in the approaches necessary in working with fetal material. A
highly critical attitude in evaluating evidence is established at the
outset by the careful analysis here made of the extent to which
normal environmental conditions of the fetus are approached by
different types of operative procedures.
Chapters 11, 111 and IV, on the fetal cardiovascular mechanism,
deal with a field that is especially difficult to handle judiciously at
this particular time. The subject bristles with long smouldering
controversies of the type which could readily be fanned into exchanges of profitless polemics, as opinion swings one way or another
with the acquisition of new, - and often seemingly contradictory, evidence. Windle has maintained a restrained and open-minded
attitude in presenting both the older and the newer phases of the
work in this field which is particularly admirable in view of his own
active participation in the studies involved. Especially constructive
is his recognition of the fact that fluctuating pressures in the umbilical circulation, due to the effects of uterine contraction or relaxation,
may quite possibly alter periodically the manner in which blood
passes through the fetal cardiovascular system. It would seem that
more emphasis might have been placed on this factor in attempting
to interpret the significance of the widely varying results obtained
by different investigators from determinations of oxygen saturation
made at various critical situations in the fetal circulation. Temporary changes in relative pressures may well be involved in a disturling manner also in injection experiments designed to ascertain the
course of blood through the fetal heart, a possibility which Windle
suggests but, -perhaps wisely in view of the fragmentary character
of our present knowledge as to pressures,-does
not attempt to
In the field of postnatal circulatory changes the author’s first-hand
acquaintance with the important m7ork of the Barcroft, Barron,
Barclay group of Cambridge, England, makes him a particularly
interesting commentator. The probability, as indicated by the recent
studies of this group, that functional closure of the ductus arteriosus
through muscular action occurs in advance of its leisurely structural
closure is most interesting and significant. That functional closure
of the foramen ovale occurs months before its anatomical closure
has now for some time been widely accepted. A similar situatioii
with regard to the ductus is so appealing on theoretical grounds that
a little extra caution in evaluating the evidence is indicated. It
should be borne in mind that an initial tendency on the part of the
circular smooth muscle of the ductus to contract, does not necessarily
imply a contraction sufficiently strongly and steadily maintained to
shut off all blood flow during the 6 to 8 weeks occupied by morphological closure. The dramatic quality of an immediate muscular
response should not cause us to forget the importance of the slower
but more positive structural closure. In this connection Windle’s
contention (p. 46) that if the ductus did not close promptly “one
should expect t o hear the characteristic murmur of a patent ductus
in every infant” must be taken with some reservations. Gross in his
brilliant paper on ligation of the ductus arteriosiis, which appeared
subsequently to Windle’s writing of this section,l has pointed out
that even children in whom the ductus had remained so fully patent
as t o justify surgical intervention might have failed to exhibit any
murmur during early infancy. This suggests that a characteristic
murmur, even when a patent ductus undeniably exists, may not be
audible until a considerable excess of systemic over pulmonary
pressure has been built up. It is quite possible that this may not
occur until after the time when the ductus would, in the normal
course of events, have been anatomically sealed. Certainly the preponderance of the left over the right ventricular wall is developed
very slowly, its full degree not being reached until the fourth or
fifth year after birth; and the development of this preponderance
must be correlated with the increase of systemic above pulmonary
pressure. These comments should not be taken as minimizing the
possible importance of a sphincter-like action of the muscle of the
ductus arteriosus in accelerating postnatal circulatory changes. They
merely suggest the necessity of revising our ideas on this subject
with the deliberation indicated by the complexity of the interacting
processes involved and the still fragmentary character of the information available as to many of their aspects.
Closely related to the matter of a smooth and efficient transition
from intra- to extra-uterine conditions in the cardiovascular mechanism is the development of the fetal respiratory system to a degree
which prepares it for full functional activity a t the moment of birth.
Chapter V contains an interesting review of the modern physiological and chemical methods which are just beginning to be brought
to bear on the study of the gaseous interchanges between fetus and
mother. The intensely interesting matter of respiratory movements
on the part of the fetus in utero is considered in Chapter VI. The
experimental evidence that is forcing the abandonment of the old
idea of complete inactivity of the respiratory mechanism during
prenatal life is covered in considerable detail. There is also a good
Gross, R. E. 1940 Experiences with surgical treatment in ten cases of patent
ductus arteriosus. J. A. M. A., vol. 115, pp. 1257-1262.
presentation of the present status of the controversy as to whether
tentative respiratory movements are regularly carried out, or
whether fetal anoxemia precipitates them a t irregular intervals. The
most interesting thing to most of us, however, will be not the controversial details but the arresting new conception that there may be
some sort of tentative “trying out” of the mechanism of respiration
even though the fetus is developing submerged in the amniotic fluid.
As is the case with the circulatory system, we are beginning to see
a respiratory mechanism more fully prepared and tested for its
postnatal role than we had previously realized. It is still true that
as individuals we crowd into a few crucial moments the change froin
water living to air living that in phylogeny must have been spread
over eons of transitional amphibious existence. But as we learn more
about this change in manner of living, it becomes apparent that we
should marvel more at the completeness and the perfection of the
preparations for its smooth accomplishment, and dwell less on the
old theme of the revolutionary character of the changes involved.
In Chapter VII on the fetal digestive system there are assembled
observations from many sources which taken together tell the interesting story of intra-uterine swallowing reactions as they involve
the amniotic fluid. Here Windle seems momentarily to relax his
usual highly critical attitude when he presents De Snoo’s somewhat
startling method of treating polyhydramnios, without a t least commenting that the facts rested on very few cases, and the conclusions
drawn from them seem a bit bold. When one reflects that the fetus
is apparently accustomed to imbibing amniotic fluid composed in
part of urine, with a dash of verniv caseosa, and possibly a t times
some meconial thickening, one should not be accused of being
obnoxiously skeptical for wondering just a little as to the effect of
adding a touch of saccharine to such a mixture. Would a little
sweetening of the amniotic fluid really make it so much more palatable that a fastidious fetus which had hitherto not been drinking
freely would promptly respond by drinking so much more that the
hydramnios would be effectively reduced? The facts cited in evidence, namely that saccharine was recovered from the blood and
urine of the fetuses, prove no more than that amniotic fluid with
whatever it happened to contain had been swallowed. This no one
would doubt. What one would like to know more about is the
alleged response to the saccharine.
Chapter VIII on the kidneys, fetal fluids, and skin brings together
in interesting fashion an extremely varied mass of material that with
less skillful handling could easily have been a mere jumble of ideas.
Particularly interesting is the suggestive opening of the almost
untouched field of the changes in the mechanism of elimination a t
the time of birth.
To one lacking first-hand experience with the meticulously detailed
observations necessary to make any sound progress in functionally
correlated studies on the developing nervous and muscular systems,
there is likely to be some feeling of disappointment in reading
Chapters IX-XI11 which deal with this field. Much that one would
like to know more explicitly is merely suggested in sketchy outline
or left untouched. That, however, is the state of our present
knowledge of the field. It is to Windle’s credit that he scrupulously
refrains from the temptation to fill in even the most intriguing of
these gaps by conjecture. In passing one cannot refrain from commenting that this temptation to paint in blank spaces impressionistically always seems to be peculiarly difficult t o resist when the
nervous system is concerned. These chapters should be provocative
in their clean-cut presentation of the start that has been made in
this difficult field and even more so in their outlining of the tremendous gaps that need to be filled by further investigation.
The two final chapters deal with the endocrine glands, and with
fetal nutrition and metabolism. The reader cannot fail t o be appreciative of the enormous amount of material collected from widely
scattered sources and here organized into logical sequence and
critically analyzed.
Thinking back over the book as a whole, one realizes that its
simple unpretentious style is well adapted to its objective. Extraordinarily few typographical errors are encountered and the figures
for the most part have been well selected, although a few of them
have been somewhat too much reduced so that consulting them
requires an unnecessary struggle to see details. A carefully made
index adds greatly to the general useability of the book. Perhaps
above all one is impressed by the tremendous range of subjects
covered and the careful documentation of the statements made, particularly in controversial fields. The resulting lists of references
at the ends of the chapters will be of particular interest to investigators. This reviewer, however, keenly regrets the employment of that
form of citation which omits the title of the article. It makes a
bibliography much less satisfactory to consult a t the time of reading,
and greatly lessens its value as a readily utilizable source of new
material for one’s own working files. The only justification for
using such an abbreviated method of citation would seem to be the
shortening of references to the point where they could appear as
footnotes on the page one is reading. If one is forced to turn to a
special bibliographical section, one is certainly entitled to find the
references complete with titles. One resents being forced t o go to the
library for information that the author readily could have placed a t
one’s immediate disposal if the publisher had not been niggardly.
There is another matter in connection with the manner of giving
citations that seems to call for comment. In the case of collaborative
papers, the fact that one who takes the trouble to follow the text
reference back to the bibliography can usually find fuller citation,
does not seem sufficient justification for giving text or figure references by mentioning only the name of the senior author and relegating his collaborators to the anonymity of “et al.” Not infrequently
the major part of the actual work has been done by a junior author
and the more junior he is the more important to him is proper
recognition. Similarly, the fact that someone’s original drawing
appealed sufficiently to the writer of a textbook so that it was incorporated in one of his plates should not relieve one who subsequently
borrows from the first borrower from crediting the original source.
These minor criticisms should receive only passing consideration.
What is of importance is that Dr. Windle has made available to us
a book which ably covers a n extraordinarily wide field in brief,
readable, and richly documented form. Moreover, much of the field
lies in what has been a sort of no-man’s-land between two conventional disoiplines. The wealth of the provocative new material
assembled in it should prove a real stimulus to students and investigators in both physiology and embryology.
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