844 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Improvements in the Silver-nitrate Method for Staining Nervous 

 Tissue.* — Dr. C. Martinotti obtains the silvor-uitrato reaction in largo 

 pieces of tissue, e. g. pons Varolii, by altering Golgi's mctLod as 

 follows : — (1) The quantity of silver-nitrate is increased relatively to 

 the size of the object. (2) Tho solution is allowed to act for 13-30 

 days. (3) The i)ieces arc kept at a temperature of 25^, iu order that 

 the reaction may reach tho ganglion cells, but in order that all the cells 

 of the nem'oglia should participate in the reaction, a temperature of 

 3o'^-40' is necessary. 



If 5 per cent, of glycerin be added to tho solution, the reaction in 

 the ganglion cells and their ramifications is facilitated. In order to 

 prevent precipitates forming at the periphery of the pieces, these were 

 imbedded in a mass made out of filter paper and distilled water after 

 tho objects had been taken out of Miiller's fluid. This artifice was 

 found to increase the contraction of the silver nitrate solution. 



Staining in the Study of Bone Development.! —Dr. J. Schaffer in 

 a large and ditfuse article recapitulates the various stains which have 

 been recommended from time to time for staiuiug cartilage in the tran- 

 sition stage to bone so as to ditferentiato the osseous and cartilaginous 

 elements. The method upon which the author dilates most was invented 

 by Bouma, who found that safranin imparted a yellow colour to tho 

 cartilage, while the connective and osseous tissues appeared red. This 

 yellow stain was supposed by Bouma to be due to the fact that safranin 

 is not a chemically pure substance, and starting from this observation, 

 the author proceeded to examine the relative staiuiug capacities of several 

 kinds of safranin in watery solution (1:2000). (1) The commercial. 

 (2) Pheno-safranin a chemically pure dye. (3) Tetraethyl-pheno- 

 safranin, a substance w^hich contains NaCl. The commercial safranin 

 gave the best differentiation, cartilage orange, bone colourless, medullary 

 tissue red. The pheno-safranin gave similar but less marked results. 

 The tetraethyl-pheuosafrauin stained the cartilage red-violet, the bono 

 and medullary tissue blue. The author then gives his method for 

 fixing the stain, a 1 : 2000 watery solution of safranin. 



The unstained sections, decalcified in nitric acid or in hydrochloric 

 acid and salt solution, are placed for half an hour in the safranin solu- 

 tion. They are then washed in water and transferred for 2 to 3 hours 

 to 1/10 per cent, sublimate solution and mounted in glycerin. If, 

 however, the preparations are to be fixed nj) permanently, the sections 

 on being removed from the sublimate solution must be passed rapidly 

 through alcohol, dried upon the slide with bibulous paper, and left for a 

 long time in oil of cloves or bergamot. They are then mounted in 

 xylol balsam. 



Preparing and Staining Mammalian Testicle.^ — For hardening 

 the mammalian testicle, Dr. A. Prcnant found that osniic acid and 

 Flemming's fluid were the best media, Kleineuberg's picro-sulphuric 

 acid, nitric acid, strong oxalic acid, absolute alcohol, 3 and 4 per cent, 

 bichromate of potash being less effective. A 1 per cent, solution of 

 osmic acid acting for one to two hours gave the bust results. Of the 



* Cungrosso IMeclico di Pavia, Seduta Cu, Kiforma Med , 12 Ott., 1887. Cf. 

 Zeitschr. f. Wiss. IMikr., v. (1888) p. 88. 



t Zeitschr. f. Wiss. Mikr., v. (1888) pp. 1-19. 



i luteruat. Monatsscbr. f. Anat. u. Physiol., iv. (1887) pp. 35S-70. 



