ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 99 



S gram, distilled water 100 grams. The solution is left to ripen 

 for eight to fifteen days at a temperature of 37° C. 2. Watery eosin 

 1 gram, distilled water 100 grams. Stain for two or three hours, for 

 preference, with a weak solution of the stain — one drop of the eosin 

 stain, and one or two drops of the blue stain to 20 c.cm. of neutral distilled 

 •water. 



Rapid Examination of Malarial Blood.* — E, Roubaud recommends 

 the following rapid method of detecting malarial parasites : — A thick 

 blood-film is quickly dried by heat (45°-55^C.) aud then hsmolyzed 

 for five to ten minutes in distilled water. This technique destroys the 

 parasite but leaves the distinctive yellow-brown pigment, which can be 

 shown up more clearly if the film is stained for a few seconds with carbol- 

 violet or thionin. In benign tertian infection the irregular streaks of 

 :small pigment-granules of the schizont can be distinguished with ease 

 from the masses of pigment of the female gamete and the dense 

 platelets of the male. The form of the other species of parasite are 

 not so easily demonstrated. For the rapid detection of crescents the 

 author places the dried thick film in a solution of thionin in distilled 

 water, of the strength of 1 to 10,000, for ten to fifteen minutes. The 

 li^molysis of the film and the staining of the crescents occur simul- 

 taneously. 



Staining Sporogenous Bacteria.f — L. Tribondeau makes a film 

 from the culture in the usual way, and then fixes it by passing through 

 the flame of a Bunsen six to ten times. When cool the slide is covered 

 with LugoFs solution and then heated to vaporization. Next the film 

 as covered with carbol-crystal violet and then heated to vaporization. 

 After a wash in tap-water, the slide is covered with an aqueous solu- 

 tion of vesuvin (1 to 500). This is allowed to act for one to two 

 minutes. After a wash in tap-water it is dried. The spores stand 

 out a dark violet against the yellow-brown bodies of the bacteria. 

 Instead of the foregoing, carbol-fuchsin and methylen-blue may be used 

 .as stain and counterstain. 



Staining Young Eels. — A. Gandolfii Hornyold sends the following 

 method, which he hopes may interest readers of the Journal. He writes 

 from the Marine Biological Laboratory, Mallorca : — '' In small eels the 

 •ovaries and the testicles have exactly the same appearance, . namely, 

 that of a very fine transparent band or ribbon, and it is only when 

 the eels are about 24-26 c.cm. long that it is possible to distinguish 

 the two sexes with a pocket-lens. Walter, in his monograph, ' Der 

 Tenpaal,' advises to examine a fragment of the organ under the micro- 

 scope with a low-power x 50. If no eggs can be distinguished, the 

 eel is most probably a male. The following method gives good results : 

 I pour a little alcohol (90 p.c.) on the organs, and it istheti quite 

 easy to detach a fragment with a fine forceps, as coagulation renders 



* Bull. Soc. Path. Exot., x. (1917) pp. 702-3. 

 t C.R. Soc. Biol. Paris, Ixxx. (1917) pp. 880-1. 



H 2 



