292 JOURNAL OF COMPARATIVE NEUROLOGY. 
foetus, was fixed by injection zz sztu of copper bichromate 5 % 
1 vol. + formalin 1 vol and further hardened, after removal, in 
copper bichromate 3% 9g vols. + formalin 1 vol. for about a 
week. A method pursued with some selachian material for the 
study of the cranial nerves will be described below. 
In order to give an idea of the various combinations of 
mordanting and decolorizing tried upon the above material a 
condensed list is given below together with the general charac- 
ter of the results. The staining fluid used was either WEIGERT’S 
alkaline haematoxylin (abbreviated in the list to ‘‘A. h.”’) ora 
neutral haematoxylin solution composed of 1 vol. of 10% solu- 
tion of haematoxylin in absolute alcohol + g vols. of water 
(‘‘N. h.”’). Where the kind of haematoxylin solution used is 
uncertain the abbreviation is ‘‘H.’’ The word ‘‘osmic”’ indi- 
cates that the section was placed in osmic acid. When this was 
done after the removal from the haematoxylin the section was 
simply rinsed in water, placed in 4% % + solution of osmic acid 
for 4% to I minute and then rinsed again in water, previously to 
decolorization. 
A. Celloidin sections of material (principally cord of infant and of 
eight months foetus) fixed and hardened in potassium bichro- 
mate + formalin as above described : 
Copper acetate. A.h. Pal. Failure. 
2.. Copper acetate. A. bh.; H. and N. h. Osmic. Pale iia. 
sults often good, in some cases fine preparations. 
3. Copper acetate. Osmic. A. h. Pal. Not very good. 
4. Copper acetate. Osmic. A. h. Osmic. Pal. Fine results. 
5. Copper acetate. H. Borax-ferricyanide. Not very good 
results—distinctly inferior to the Pal. 
6. Copper acetate. H. Osmic. Borax-ferricyanide. Some- 
what better than 5. 
7. Copper bichromate. A.h. and N. h. Borax-ferricyanide. 
Not good. 
8. Copper bichromate. H. Pal. Good. 
Copper bichromate. H. Osmic. Pal. Very good. This 
gave the best results of any combination. 
to. Copper bichromate. N.h. Ironalum. Failure. 
11. Copper bichromate-+ osmic. A. h. Pal. Failure. 
Lal 
