434 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
of immersion in acid solution. Remove tooth (molar) at end of seventy- 
five to eighty hours, and wash in solution of lithium carb. (5 grm. to an 
ounce) for half an hour. Wash thoroughly with distilled water. 
Divide tooth by razor into several pieces, and wash again in water. 
Place each piece in gum mucilage (B. P.). Leave in mucilage twelve 
to fifteen hours. Transfer to stage of freezing microtome, cut, wash 
sections, and stain with orange-rubine, or gold chloride, or borax- 
carmine, or Weigert’s solutions. Dehydrate in absolute alcohol three 
minutes, clear in cedar oil one and a half minutes, and mount in 
Canada balsam.” 
Investigation, of Brain of Marmoset Monkey.* — Dr. C. E. Beevor, 
who has studied the fibi'es of the cingulum and the corpus callosum and 
fornix in the Marmosets, put the brains direct into a 3 per cent, solution 
of bichromate of potassium, where they were hardened from two to four 
months, and in one case for twelve. After hardening the brain was 
imbedded in celloidin and cut into sections by Schanze’s microtome. 
Weigert’s hematoxylin method, or Pal’s modification thereof was used 
for staining. The sections were dehydrated by absolute alcohol, clari- 
fied by oil of cloves or origanon oil, and mounted in Canada balsam. 
The advantage of origanon oil over oil of cloves is that it does not 
dissolve out the celloidin, which is thus able to hold together the finer 
parts of the section, and prevent it from falling to pieces in the process 
of clarifying. The objection to it is that the sections do not remain 
perfectly flat. To obviate this some of the sections were dehydrated on 
the slide, the absolute alcohol was run off without disturbing the 
sections, which were then clarified by adding origanon oil. When this 
was completed the oil was run off, and oil of cloves was carefully added. 
This was run off after dissolving the celloidin. 
Some of the sections were cut after imbedding in paraffin. The 
brain was hardened in methylated alcohol, put for two weeks in a 3 per 
cent, solution of bichromate of potash, washed in water and in methylated 
alcohol, aud put direct into Weigert’s liasmatoxylin for three or four 
days. 
Preparation of Eggs of American Alligator.} — Mr. S. F. Clarke 
carefully removed the shell and its membrane from nearly half one side 
of the egg ; the contents were then poured out on to the left hand, and 
the thick white at one end cut off with the scissors. The egg is then 
replaced in the shell with the germinal pole, still covered with white, 
uppermost. The white is next cut off as completely as possible from 
this end. The egg is now set on end, aud a sharp-edged lifter is used 
to press out on either side incisions made with sharp-edged scissors. 
By this means the portion of the blastoderm which contains the embryo, 
and measures from 12 to 15 mm., is separated from the rest. The 
embryo is treated with Kleinenberg’s picric for sections, or chromic acid 
for surface study. 
Preservation of Tadpoles.} — Mr. G. A. Boulenger recommends the 
collector of tadpoles to provide himself with small test-tubes half-full 
* Philosoph. Trans., 182 B (1892) pp. 137-8. 
t Journal of Morphology, vi. (1891) pp. 202 3. 
J Proc. Zool. Soc. London, 1891 (1892) p. 599. 
