378 SUMMARY OF CURRENT RESEARCHES RELATING TO 
bichromate of potash and copper sulphate in 50 per cent, alcohol, Rabl’s 
platinum chloride and picric acid ; and succeeded well in demonstrating 
the intercellular bridges. After fixing he stained his preparations with 
a solution of rubin (patent-acid rubin *25 grm., 2 per cent, acetic acid, 
saturated picric acid 100 grm.), using 3-4 ccm. to 100 ccm. of absolute 
alcohol. Golgi’s silver method also gave good results. 
Examination of Central Nervous System of Desmognathus fusca.* 
— Mr. P. A. Fish decalcifies the cranium of this salamander by Perenyi’s 
mixture or Gage’s decalcifier. The latter is made up by adding 3 ccm. of 
strong nitric acid to 100 ccm. 70 per cent, alcohol, and gives uniformly 
good results. The tissue was fixed either by potassium bichromate, cor- 
rosive sublimate, picric alcohol, or a mixture which may be called picro- 
aceto sublimate. This last is composed as follows : — 50 per cent, alcohol, 
1000 ccm. ; glacial acetic acid, 5 ccm. ; corrosive sublimate, 5 grm. ; 
picric acid, 1 grm. This gave most satisfactory results, and brought 
out many histological details that were not demonstrable by the other 
methods. For staining, Delafield’s haematoxylin gave most excellent 
results. Contra-staining with Van Gieson’s picro-fuchsin gave most 
brilliant effects. Herrick’s modification, which consists in adding a 
tablet of • 5 of a gram of corrosive sublimate and * 5 grm. of ammonium 
chloride to about half a litre of the stain, was found to work very satis- 
factorily. Another satisfactory modification is the addition of 1 ccm. of 
glacial acetic acid and 1 ccm. of a saturated aqueous solution of corrosive 
sublimate to 1 00 ccm. of the haematoxylin. For histological details the 
short silver nitrate method of Golgi and Weigert’s haematoxylin method 
were mainly employed. In the silver method the author used 3 per 
cent, potassium bichromate 100 ccm., 1 per cent, osmic acid 20 ccm. 
The tissue was allowed to remain in this mixture from 24 to 48 hours, 
according to the temperature. It was then rinsed rapidly, and placed in 
a weak solution of 1/4 per cent, silver nitrate for 15 or 20 minutes. 
This was changed a couple of times until the fluid remained clear. It 
was then immersed in a 3/4 per cent, silver nitrate solution, and left 
there for two days or longer. The object was cleared and cut in a 
mixture of 3 parts red oil of thyme and 1 part of castor oil. 
If the specimen is stained in toto the method is a very expeditious 
one. It was found that the sections, after absorbing the superfluous oil 
with tissue paper, could be fixed to the slide by means of a drop or two 
of ether-alcohol, and that they might then be passed through the various 
alcohols, and stained similarly to the paraffin or ordinary collodion 
methods. Any tendency toward crumbling or tearing on the part of 
the sections may be obviated by painting the cut surface of the object 
with a thin layer of 1 per cent, collodion before making each cut ; this 
will also enable one to cut much thinner sections. 
Preparation of Fish Eggs.j — Mr. J. T. Cunningham has found it 
very difficult to preserve fish ova satisfactorily for cutting, as the ger- 
minal vesicle, or the protoplasm, or both, are more or less destroyed by 
the preserving reagents. He finds that the much-vaunted mixtures of 
Flemming, namely, chromic, osmic, and acetic acids are not satisfactory, 
* Journ. Morphol., x. (1895) pp. 234-5. 
f Journ. Mar. Biol. Ass., iii. (1895) p. 270. 
