852 SUMMARY OF CURRENT RESEARCHES RELATING TO 



For cover preparations the glasses used by him are from • 01-0 • 012 in. 

 thick. The sputum is pressed into a thin and even layer, and before 

 separating the two covers they are laid on a hot plate at a temperature of 

 nearly 100° C. until coagulation, shown by opacity, occurs. 



For staining, the author usually employs anilin-fuchsin, and for decolora- 

 tion nitric acid diluted with 2 parts of saturated sulphanilic acid. De- 

 coloration is not continuous, but is performed at intervals of a few seconds, 

 and each time the acid is thoroughly washed away. 



For demonstrating tubercle bacilli in fragments of tissue where thin 

 sections are only obtainable with difficulty, the author adopts the following 

 method : — 



(1) Stain cover preparations in watery solution of fuchsin for twenty-four 

 hours. (2) Anilin-fuchsin for twenty-four hours. (3) Wash in spirit, or 

 for a short while in sulphanilin nitric acid, afterwards washing with water 

 carefully. (4) Immerse in concentrated solution of sodium sulphide for 

 twenty-four hours, and then transfer to a vessel filled with recently boiled 

 water. (5) Dry the preparation and examine, without contrast staining, 

 in balsam. 



Chemistry of Staining.* — Herr P. G. Unna has made a further 

 contribution to the chemical theory of staining. He has previously shown 

 that two reagents, metaphenylenediamine and nitric acid, which outside the 

 tissue at once unite into the brown triamidoazobenzol (vesuvin), when 

 separately introduced into the tissue lose this affinity. He has utilized 

 sections of leprous skin hardened in alcohol for the corroboration of his 

 theory of the occurrence of a chemical process in staining. This tissue 

 was peculiarly suitable as containing within a minimum space the most 

 diverse vegetable and animal substances. 



By mixing equal parts of an aqueous solution of metatoluylenediamine 

 and hydrochloric acid with nitrosodimethyl anilin, there results the beautiful 

 deep-blue solution of toluyelene-blue. When sections of the above skin are 

 treated with 1 per cent, of this blue in aqueous-alcoholic solution they stain 

 blue. The vegetable parasites become dark-blue, and by solution in certain 

 acids the general blue colour of the rest of the section is replaced by red 

 in certain regions. But if the two components be introduced separately 

 into the tissue the result is quite different. The difference is carefully 

 analysed, and a chemical explanation offered. It is impossible to summarize 

 the chemical details by which the author seeks to corroborate his point. 

 By union with the tissue a colouring substance may lose its reducibility 

 or another its power of being oxidized. In some cases the section appears 

 to act as an alkali. The paper is an interesting attempt to rationalize our 

 highly elaborated technique. 



Feekb, J.— Acide osmique et precede d'Ehrlich dans la preparation du bacille de la 

 lepre. (Osmic acid and Ehrlich's process in the preparation of the bacillus of 

 leprosy.) Journ. de Med. Bordeaux, 1887, p. 622. 



Gedoelst, L. — Un nouveau procede pour preparer le picro-carmine. (New process for 

 preparing picro-carmine.) Moniteur da Fract., III. (1887) p. 91, 



G ij N T H E R, C. — Ueber die mikroskopische Parbung der wicbtigsten patbogenen Bac- 

 terien mit Anilinfarbstoffen. (On the microscopic staining of the most important 

 pathogenic bacteria with anilin colouring matters.) 



Deutsche Med. Wochenschr., 1887, pp. 471-5. 

 Imada, Y. — An improved Fluid for Injection. 

 [Transl. from the 'Chu-gwai Iji-schimpo.] 



Sei-i-Ku-ai Med. Journ. Tokio, VI. (1887) p. 7, 



* Arch, f. Mikr, Anat,, xxx. (1887) pp. 38-48. 



