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The method of making models from sheets of blotting paper.

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THE METHOD O F MAKING MODELS FROM SI-IEETS O F
BLOTTING PAPER.
BY
SUSANNA PHELPS GAGE.
Ithaca, New York.
The Born Method of reconstructing models from wax plates is in use
in all the larger laboratories of Anatomy and Embryology. Various
modifications of that method have been introduced, notably at Johns
IIopkins University. For smaller laboratories and isolated investigators
the wax plates are difficult to prepare or to obtain already made. Moreover, in the larger laboratories ihe preparation of the plates is a much
dreaded piece of drudgery to be done in the basement. The apparatus
is cumbersome and if at all accurate, expensive. Like any other apparatus it requires some skill to use it with success. Any one who has
either cast or rolled wax plates will not need a statement of the
inconveniences.
I n 1905, it occurred to me that sheets of blotting paper might serve
instead of wax plates. A small model was at once made which showed
its feasibility. Models made of this material were demonstrated at thc
Association of American Anatomists in December, 1905, ( Amer. Jour.
Anat. V., 1905-06, p. X X I I I ) and the method was further demonstrated
at the International Zoological Congress held in Boston, August, 1907'.
It has also been used successfully in the embryologic and anatomic
laboratories of Cornell University and the University of West Virginia.
Blotting paper models were demonstrated by Dr. J. H. Hathaway and
by Dr. J. B. Johnston a t the Association of American Anatomists held in
New York, 1906 (Proc. Assoc. Amer. Anatomists, Anat. Record, April
1, 1907,).
Usually with the Born method the wax plates are 1, 2, or 3 mm. in
thickness and the sections of the specimen are l o p or some other multiple
of 5, thus making the magnification a t which the drawing of the sections should be made, a simple problem in proportion.
It has been objected that it is difficult to obtain blotting paper of a
given thickness. This is indeed true. I n Ithaca, a t a wholesale paper
dealer's one package was bought in which the paper was of the desirable
Nov. 10, '07.
The Anatomical Record
167
thickness of one millimeter. The thickness since obtainable is 0.5 nim.,
0.77 mm. and 0.9 mm.
The following steps give a general outline of the method used:
1. For testing the thickness, a pile of 40 pieces of the same size cut
from diffe'rent sheets of the blotting paper is held closely together by a
rubber band. One end of the block so formed is dipped in hot paraffin
and compressed with the fingers. The measurement of the parafflned end
divided by the number of pieces gives the working thickness of the paper.
2. Size of model and thickness of plates.-Suppose a model is to be
made of a specimen cut into a lop series and the blotting paper available has a thickness of 0.9 mm. or 9OOp. Each sheet is 9OOp divided by
l o p = 90 times as thick as the sections. The simplest case would be
for a model 90 times as large as the object. Then each section is
drawn at a magnification of 90 and a plate of the blotting paper is used
for each section.
Suppose it were desirable to use a magnification of 120. Each section
is drawn of the proper size, and must be represented by a thickness on
the model of 120 X l o p = 1200p or 1.2 mm. One plate is 0.9 mm.
thick, that is 0.3 mm. less than it should be. In every three plates there
is a loss of 0.9 mm., a loss which is made good by using two sheets of
blotting paper for every third section, that is, for every group of three
sections four pieces of blotting paper would be used.
Suppose a magnification of 60 were desired, then each section if drawn
at a magnification of 60 should be represented on the model by 60 X lop
= 600p or 0.6 mm. As the thickness of the paper is 0.9 mm., one plate is
0.3 mm. too thick and three plates would be 0.9 mm. too thick. Hence if
every third plate is omitted the correct thickness is secured. In practice
the drawing of every third section is omitted.
Other problems are easily met as occasion demands by adding plates
or omitting the drawing of certain sections. The slight inaccuracy thus
produced is negligible.
3. Thickness of paper, size of model and magnification having been
determined, the drawings of sections are made upon the blotting paper
by the aid of a camera lucida, or more satisfactorily with a projection
microscope.
One or more duplicate drawings may be easily secured by using carbon
paper and thin sheets over the blotting paper.
4. The difficulty of cutting wax plates is considerable. This difficulty
has been met by Dr. E. TJ. Mark by using a sewing-machine with an
electrically heated wire as cutting edge. (Demonstrated at the Asso-
168
The Anatomical Record
Now. 10, ’07.
ciation of American Anatomists, December, 1906. Method published in
the American Read. Arts and Sciences, March, 1907. See also Science,
XXV, 1907, Anat. Record, Apr., 1907.)
With the blotting paper, if the drawings are small the cutting is
easily done with scissors or a knife. When the drawings are large and
especially when the model is to be made by representing each section
by two to four thicknesses of blotting paper it has been found that an
ordinary sewing-machine can be used to do the cutting. By setting the
regulator for the shortest stitch an almost continuous cut is made and
the parts are easily separated. If a large sewing-machine needle is
sharpened in the form of a chisel, the cut becomes considerably smoother.
It has heen found advantageous when long continued or heavy work is
to be done to attach to the machine an electric sewing-machine motor.
Skill in guiding the work is soon acquired. Therc are some details of
a complicated drawing which are more easily cut by the scissors or a
knife after the main lines have been cut by the machine.
5. It is a great advantage in any working model to have sections at
regular intervals in marked contrast with the body of the material. Blotting paper of a large variety of colors (black, red, blue, pink) is easilg
obtained in the market. In the models made every tenth plate was a
bright or light color and every lOOdth was black, rendering rapid numeration easy.
6. \Then the paper sections are thus prepared they are piled and repiled as is usual until the shape conforms to an outline predetermined
from photographs, drawings, or iueasurements made before the specimen
was cut.
It has been found that an easily prepared support and guide for the
model in process of setting up, is made by cutting the outline to be followed from a block of four or five sheets of blotting paper, marking
upon it the lines of direction for every tenth or twentieth section. The
colored numerating plates must of course conform to the spacing and
direction of these lines.
‘7. The preliminary shaping having been accomplished more exact
modeling is undertaken. The paper sections slide very easily upon one
another. The most satisfactory means of fastening them together is
by the use of ribbon pins, ordinary pins, or wire nails of various sizes,
depending upon the size of the model. No kind of paste or glue was
found suitable for this purpose.
8. When the model is well formed, inequalities are best removed by
rubbing with the edge of a dull knifc and smoothing with sand paper.
Nov. 10, ’07.
The Anatomical Record
169
Any dissections of the model for showing internal structures should be
planned for a t this stage for it is now more easily separated than later.
It is also a t this time that superfluous “bridges,” which have been left
in place to support detached parts, would better be removed.
9. T o finish the model it is held together firmly and coated with hot
paraffin either by a camel’s hair brush or by dipping in paraffin and
removing the superfluous coating by a hot instrument. On a very large
model Dr. Hathaway used a thermo-cautery for this purpose.
The paraffin renders the model almost of the toughness of wood without destroying the lightness of the paper.
10. For coloring the surface of the model, it was found most desirable
to use Japanese bibulous paper (the lens paper of the microscope dealers) which had been dipped in water color and clried. Any of the
laboratory dyes or inks can be used, such as eosin, picric acid, methylene
green, black ink, etc. The colored lens paper molds over the surface
with ease and is held in place by painting with hot paraffin. All color
and enumeration lines and fine modeling show through the transparent
paper.
When the model ceases to be a working model it can be covered with
oil paints mixed with hot paraffin and rubbed to any degree of finish
desired.
11. One can dissect the model by a hot knife run along the planes of
cleavage or cut across them by a saw.
The advantages claimed for blotting paper models arc the ease and
cleanliness of their production and the lightness and durability of the
product. The models are broken with difficulty, are easily packed or
transported, and when they cleave apart are easily repaired, thus contrastwith the weight and fragility of wax models and their deformation by
heat.
By this process are secured for the original model reconstructed from
microscopic sections, the same qualities which have made the Auzoux
models molded from papier-mache such useful and lasting additions
to laboratory equipment; and in the hands of Dr. Dwight and Mr.
Emerton, of Harvard University, have aided so much in the demonstration of structure and form of special anatomic preparations.
THD.ANATOMICAL
RECORU.--NO. 7.
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