Hibens@s Halll 443 
percentages of the caustic solution may be resorted to without danger 
to the specimens. The specimens may be studied in glycerine or by a 
method devised by Bardeen may be mounted upon glass slides and placed 
in any desired position in jars of glycerine. The objects are removed 
from pure glycerine, wiped and quickly washed. They are then placed 
in a little thick gelatin solution and are laid upon a warm glass slide. 
As soon as the gelatin is hardened the specimens are returned to the 
pure glycerine without any danger of becoming loosened from the slide. 
The purity of the glycerine should be assured, as the presence of foreign 
substances such as water may tend to soften the gelatin. 
The clearing reagents advocated by Van Wijhe* and Lundvall* did 
not give the same degree of transparency as was gained by following 
the above method, though in clearing the capsule of the adult testis 
beautiful specimens were obtained by using absolute alcohol and xylol 
as outlined by Van Wijhe. In following the distribution of the blood 
vessels in the capsule, quite satisfactory results were obtained by the 
very practical and simple method devised by Flint in his work on the 
adrenal.’ “ After carefully dissecting away all of the paricapsular con- 
nective tissue from the injected and hardened gland, it is cut in half, 
longitudinally, with a sharp razor and the parenchyma is scraped out 
with a scalpel. The remaining fibrous capsule is then treated exactly 
like a section and, after dehydration, is cleared and mounted in a cell.” 
Although the modified Schultze method is particularly applicable to 
embryonic tissues, yet sections of the adult testis 3-4 mm. thick, the 
arteries and veins of which had been injected with India ink were 
speedily rendered transparent by a clearing treatment similar to that 
for the less resistant embryonic tissue. 
In preparing injections for corrosion specimens of larger embryonic 
and adult testes, great difficulty was experienced until it was discovered 
that seven per cent celloidin would flow quite readily through a medinm- 
sized hypodermic needle. ‘Thus in injecting the adult sex gland it was 
only necessary to find the point at which the spermatic artery reached 
the gland in order to avoid the difficulty met with in forcing the in- 
jection mass through the many coils of artery which lie in the cord of 
the pig near its attachment to the epididymis. 'The corrosion was ac- 
complished with hydrochloric acid and pepsin, after which the specimens 
5 Van Wijhe, J. W.: A New Method for Demonstrating Cartilaginous Mikro- 
skeletons. Kononklijke Akademie van Wetenschappen Te Amsterdam, 1902. 
®Lundvall, H.: Ueber Demonstration Embryonaler Knorpelskelette. Anat. 
Anz., pp. 219-223, Band XXV. 
