ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 383 



a silver salt and subsequently exposing it to the action of a reducing 

 agent. After a number of experiments, it was found that while, in the 

 case of chicks of two or three days' incubation, the best results were ob- 

 tained with perfectly fresh tissue, a certain amount of post-mortem 

 change was an advantage in older embryos, the optimum period varying 

 from 12 hours in the case of a four-day chick to 24 or 36 hours in the 

 case of adult animals. 



By this method fully-developed nerves are stained dark brown, almost 

 black, while the rest of the tissues are golden yellow. Nerve-fibres stain 

 better than nerve-cells. In embryonic tissues, developing nerves are 

 stained in accordance with their degree of development. In preparations 

 stained by this method, nervous tissue, in addition to its dark tint, shows 

 a peculiar sheen which differentiates it from deeply stained portions of 

 non-nervous tissue. Many sections show signs of deterioration after a 

 lapse of about two years. 



Studying the Morphology of the Blood of Amphibia.* — F. Freid- 

 sohn exposed the slides to be used to the vapour of pure formalin for 

 2 minutes, then made a smear in the usual way, and again exposed to 

 formalin vapor, this time for about 1 minute. Osinic acid vapor did not 

 yield good results. The fixed smears were air-dried and stained as 

 follows : To 50 cent, of distilled water were added fifteen drops of Giemsa 

 stain and five drops of 2 p.c. aqueous eosin solution (extra B.A.) — this 

 was allowed to act for from 1 to 2 hours. The preparations were then 

 washed with water, dried and mounted. The author's observations are 

 confirmatory of the view that the red and white corpuscles develop from 

 lymphoid cells ; the illustrations in regard to the polymorph leucocytes 

 are specially convincing. 



Studying the Varicosities on Non-medullated Nerve-fibres.f — A. 

 Xemiloff first treated the fresh material in | to t l p.c. solution in 

 1'6 p.c. saline; after allowing the stain to act for h to H hours the 

 preparations were fixed in 8 to 10 p.c. molybdate of ammonium, to which 

 a few drops of formalin or of osmic acid solution were sometimes added. 

 After fixation the preparations were washed in water, rapidly dehydrated 

 in absolute alcohol, cleaned in xylol, and mounted in Damara. 



Ceil Inclusions in Rabbit's Liver.} — L. Launoy observed certain 

 protoplasmic inclusions in the liver of the normal rabbit by means of 

 the following procedure : When the liver-cells are dissociated in a solu- 

 tion of brilliant cresyl-blue (rouo-o- t° 2§-<yoir)> the presence of certain 

 inclusions may be seen, and also at the periphery some hard, highly- 

 refracting, often pigmented, yellow or yellowish-brown bodies, which 

 stain blue. Treated with the sulphate of nile blue CxoVir t° Winr) aiK ^ 

 naphthol blue CswoOj these granules stain blue or reddish violet respec- 

 tively. The staining is selective, as no other intracellular granules are 

 stained under the same conditions. The granules are insoluble in 

 alcohol and chloroform in presence of acetic acid ; osmic acid is feebly 



* Arch, ilikrosk. Anat. u. Entwickl., lxxv. (1910) pp. 436-72 (1 pi.). 



t Tom. cit., pp. 567-9 (1 pi.). 



t Comptes Rendu*, cl. (1910) pp. 145-8 (2 figs.). 



