ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
755 
(4) Staining and Injecting 1 . 
Modification of Golgi Silver Stain.* — Dr. H. J. Berkley lias chiefly 
followed, in the investigation of the nerves of the liver, the rapid Golgi 
method, but he did not always get with it the finest details. He 
recommends, therefore, the following modifications : — The tissue is cut 
into slices not more than 1 • 5 mm. thick, and while warm is immersed in 
a saturated solution of picric acid diluted with an equal volume of warm 
water. After being in it for from 15 to 30 minutes it is immersed, 
without washing, in the hardening fluid, where it remains for forty- 
eight hours or longer. This fluid should consist of aqueous solution 
bichromate of potash 100 parts (saturated in the sunlight), and solution 
of 2 per cent, osmic acid, 16 parts. The solution is to be exposed to 
full sunlight to age, but all specimens are to be hardened in absolute 
darkness at a temperature not lower than 25° C. 
After the expiration of the 48 hours the specimens are treated 
with the silver solutions of 0*25 and 0*75 percent, in the usual manner, 
and allowed to remain in them five or six days. After very rapid wash- 
ing in running water they are rapidly dehydrated, immersed for a few 
minutes in celloidin, placed on a cork, and the celloidin hardened in 
75 per cent, alcohol in a closed jar ; this jar is cooled so as to harden 
the celloidin as rapidly as possible. The sections are cut under 95 per 
cent, alcohol, rapidly dehydrated, cleared in oil of bergamot, and 
mounted in xylol-balsam without cover-slip. 
The osmium-copper-hsematoxylin method and various gold methods 
were tried, but the results do not appear to have been very satisfactory. 
Staining Intrinsic Pulmonary Nerves of Mammalia.f — For these 
nerves Dr. H. J. Berkley found that the picrid-acid-osmium-bichromate 
modification gave incomparably better results than the rapid Golgi 
method, the latter allowing no definite distinction to be made between 
medullated and non-medullated nerves. 
Nerve-Supply of Cardiac Ventricles.J — The same author reports 
that very considerable differences are found in the staining by the 
silver methods of the nerve elements in the muscular tissue of the cardiac 
ventricle. These variations in the staining action of the silver salt 
account in large measure for the discrepancies that exist between dif- 
ferent observers that have used Golgi’s method. 
Staining Living Cells.§ — Dr. G. Galeotti finds, from numerous 
experiments on animals and plants, that living cells never stain alto- 
gether, owing to their vital energy, which prevents the colouring matters 
from becoming diffused in their protoplasm. It is, however, possible 
to stain some elements of living cells, and those are they which do not 
take any active part in the functions of the cells ; such are the supposed 
nutritive substances of the cytoplasm and secretory products destined to 
be expelled. It cannot therefore be admitted that there is a vital staining 
reaction for the nervous system in the sense of Ehrlich, or in that of 
Schultze and Mitrophanow for the cytoplasmic granules, for the staining 
* Johns Hopkins Hospital Beports, iv. (1894) pp. 216-9. 
f Tom. cit., p. 241. f Tom. cit., p. 250. 
§ Zeitschr. f. wiss. Mikr., xi. (1894) pp. 172-207. 
