514 SUMMARY OF CURRENT RESEARCHES RELATING TO 



cent, of corrosive sublimate), are placed in a solution of sulphide of soda. 

 The mercury, already reduced from the sublimate, is changed into sulphide, 

 and the preparations become blackened. The tissue, which has not under- 

 gone the influence of the foregoing reaction, is stained with a solution of 

 Magdala red, which gives extremely beautiful pictures. Even Golgi's 

 nitrate of silver method is improved by after-treatment with sulphide of 

 soda. 



China-Blue as a Stain for the Funnel-shaped Fibrils in Medullated 

 Nerves.* — Signer C. Galli has succeeded in staining with China-blue 

 the spiral or funnel-shaped fibres of the myeline sheath of peripheral 

 nerves, about the existence of which there was once considerable dispute. 



The procedure, which is very simple, is as follows : — The sciatic nerve, 

 carefully cut out from a recently killed animal, is placed in Miiller's fluid 

 for eighteen to twenty days. It is then cut up into pieces 5 or 6 mm. 

 long, and these pieces are placed for one or two days in a mixture of one 

 part Mliller and two parts water. They are then cut up lengthwise, and 

 immersed in a few drops of glycerin to which glacial acetic acid has been 

 added in the proportion of one or two drops of acid to 1 or 2 c.cm. of 

 glycerin. In this they remain for fifteen to twenty minutes, according to 

 the greater or less acidity of the glycerin. The pieces are then placed in 

 ordinary spirit, where they lose the excess of their colour, and are then 

 coarsely teased out. They are next dehydrated in absolute alcohol, and 

 then cleared up in oil of turpentine. Lastly, a small piece is carefully 

 teased out on a slide and then mounted in dammar. 



From the author's description, it would seem that the staining is some- 

 what diffuse, so that sometimes the funnel-fibres are obscured by the darker 

 stain of the other constituents of the nerve, especially the sheath of 

 Schwann. The blue stain colours the axis-cylinder, the myeline sheath of 

 Schwann's membrane, as well as the funnel-fibres and the primitive sheath 

 nuclei. From the illustrations given by the author, we gather that the 

 axis-cylinder and the nuclei are the less colourable parts. 



New Staining Method for Sections-f— Dr. H. Kiihne thinks that it 

 is advantageous to pass sections tlirt)ugh a concentrated watery solution of 

 oxalic acid and then thoroughly wash them before staining. For this 

 purpose the author uses watery solutions of the dyes which in the case of 

 fuchsin he combines with anilin or thymol water ; of methylene blue with a 

 1 per cent, watery solution of ammonia carbonate ; of violet with anilin or 

 thymol 4- ammonia carbonate. Diflerentiation is not eftected with acids 

 and alcohol, but the sections are first dehydrated in absolute alcohol, to 

 which some of the first used dye has been added. 



Diflerentiation is attained by means of acid stains, of which fluorescin 

 is the most universally applicable. This is dissolved in oil of cloves, and 

 from the mixture the sections are passed through turpentine to xylol and 

 then to xylol balsam. 



Double Staining^ with Orcin.J — Dr. 0. Israel has introduced a new 

 dye, orcin (C4H,N0g), to microscopical and especially to bacteriological 

 technique, being suitable for most bacteria as well as for various tissues. 

 It is a vegetable dye which unites in itself the staining properties of the 

 basic and acid stains, and also the combination of two contrast colours. 



If sections of actinomycotic tissue be placed in a saturated acetic acid 

 solution, the fungus assumes a dark Bordeaux-red hue, which is the more 



* Zeitschr. f. Wiss. Mikr., iii. (1886) pp. 465-70 (1 pi.). 



t Zoitaclir. f. Hygiene, i. (1887) p. .553. 



i Virchow's Arch. f. ruth. Anat. u. Physiol., cv. (1886) p. 169. 



