ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 381 



acid 20 drops ; filter. After the two solutions have been mixed, the 

 staining solution is filtered again. Solution 2 consists of methylen-blue 

 2 "4, borax 2*5, absolute alcohol 100 ; filter. 



The procedure is simple. Drop on the film solution, and after about 

 a minute add five times the quantity of distilled water ; allow to act for 

 about 1 h minutes, then wash in tap water. Next stain with No. 2 solution 

 for soma 20-30 seconds, wash again, dry on blotting paper, and mount 

 in balsam. 



For filtration thick papers are required, especially for No. 2 solution ; 

 for this 589 Schleicher and Schiill is recommended. 



Azocarmin and Chromotrops as Contrast Stains.* — M. Heidenhain 

 has obtained good results from the use of Azocarmin B. This pigment 

 is an amido-acid, is easily soluble in alcohol, and imparts a beautiful 

 ruby-red hue. It acts more powerfully when the material has been 

 treated with some chromic acid salt. 



The advantages of the chromotrops appear to be more numerous, 

 and the author believes that they have a great future, and will supersede 

 eosin. He has experimented with four kinds of these azo-derivatives of 

 chromotropic acid, viz. 2 R, 2 B, 6 B, 7 B. The first two impart a 

 yellowish-red hue, the latter pair a bluish tone. The procedure for 

 staining is as follows : Hasmatoxylin-stained sections are transferred to 

 96 p.c. alcohol, and then treated with ammoniacal-alcohol (1 c.cm. 

 ammonia to 1 litre of absolute alcohol). This turns the sections blue, 

 and when this stage is arrived at they are placed in absolute alcohol 

 again. From the latter they are transferred to an alcoholic chromotrop 

 solution, which may be strong or weak. 



After washing with absolute alcohol, the sections are passed through 

 xylol and mounted in balsam. 



Demonstrating Cytoryctes luis.f — G. Siegel, after alluding to the 

 observations of Klebs in 1879, and of Dohle in 1892, states that he has 

 found in the body-juices and cells of syphilis a motile parasite which he 

 believes is a flagellate protozoon. 



The parasites are demonstrable in films of blood or tissue-juice, by 

 first staining with Grenacher's haematoxylin, and after differentiating 

 with acid alcohol, contrast-staining with azur ii. (1 : 1000). The 

 fiagella are stained for 3 days in Giemsa's solution, which should be 

 frequently changed, and warmed each time. 



In sections, which should be very thin (2/a), the parasites are found 

 within connective-tissue cells. 



Inoculation experiments on monkeys and rabbits were successful. 



Staining Spirochaeta pallida. J — Davidsohn recommends Kresyl- 

 violet R. extra for staining Spirochceta. As much as will go on the end 

 of a knife-blade ( ? size) is dissolved in 100 c.cm. water. 



* Zeitschr. wiss. Mikrosk., xxii. (1905) pp. 337-43. 



t Munch, med. Wochenschr., 1905, Nos. 28, 29. See also Centralbl. Bakt., 

 l te Abt. Ref., xxxvii. (1905) pp. 480-2. 



% Berlin Klin. Wochenschr, 1905, p. 985. See also Centralbl. Bakt., lte Abt. 

 Ref., xxxviii. (1905) p. 50. 



