ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 463 



legists in December 1911 on the diagnosis of cholera. Two points 

 were kept in view, viz. the possibility of examining enormons nnnibers 

 of cases with the minimum of equipment, and the rapid preparation of 

 media for immediate use in emergency. In general no medium is neces- 

 sary but peptone water. If the faeces contain a sufficient numl^er of 

 cholera vibrios, the peptone cultures after eight to twelve hours have 

 practically a pure culture at their surface. If a drop of this and 

 immune serum be mixed, the microscopic agglutination is so prompt 

 and evident as to be diagnostic. In examining carriers or mild cases 

 the first peptone tubes may show little or nothing. If, however, sub- 

 cultures be made, the second surface growth becomes sufficiently pure 

 for testing the agglutinability cf the vibrios. Vibrios other than 

 cholera can be excluded by their inability to enrich or by the absence 

 of any influence of the agglutinating serum. 



As a selective medium the following gives equally good results as 

 defilninated blood : — A. Whole egg and water aa ; sodium carbonate 

 (crystallin, 12 to 13^p.c.) ; mix in equal parts and steam for 20 minutes. 

 B. Pepton, salt and 3 p.c. agar. Mix 30 parts of A with 70 parts of B 

 while the agar is boiling hot ; pour medium to thick plates, and then 

 inoculate by surface streaking. Should other faecal bacteria grow, the 

 cholera colonies can easily be selected. The latter have a distinctive 

 hazy outhne and appear to be deep in the agar. With longer incuba- 

 tion a zone of clearing appears about the colonies. 



Demonstrating' the Presence of Capsules in Cultures of Pneu- 

 mococcus and of Pneumobacillus.*— J. Hardouin makes a filui of a 

 mixture of the culture and of Indian ink after the manner initiated by 

 Burri for demonstrating the Spimcliaeta pallida. The film is then dried 

 and fixed with alcohol, and afterwards stained with toluidin-l)lue, 

 carbolmethylen-blue, or with carbol fuchsin. The film is then washed 

 with water dehydrated with alcohol, cleared in xylol, and mounted. 

 The capsules are said to stand out with perfect clearness. 



Demonstrating the Presence of Chondriosomes.t — E. Grynfeltt, 

 when examining the cells of the hypobranchial gland of Murex trunculus, 

 employed the following methods : — Alizarin and crystal violet differen- 

 tiated with acetic-acid (Benda), iron h^ematoxylin after fixation 

 in formol-Miiller (Regaud), fuchsin differentiated with picric-acid 

 (Altmann). The author inentions that mitochondrial bodies or chon- 

 driosomes, which together constitute the chondriome (Meves) or mito- 

 chondrial apparatus (Duesberg), may present themselves in the form 

 of filaments or chondriochonts (Meves), as chains of granulations, 

 similar to streptococcus, called chondriomites (Benda), or as fine isolated 

 granulations, the mitochondria of Benda. All of them are stained 

 deeply l:)y any of the three methods given above ; but it seems unwise 

 to rely merely on these staining reactions, marked though they be. 

 Their morphological characters must also be taken into consideration, 

 especially as mitochondria are extremely like certain granules which, 

 while staining exactly in the same way, are certainly not mitochondria. 



* C.R. Soc. Biol., Ixxii. (1912) pp. 298-9. 



t Bull. Mensuel Acad. Sci. et Lettres MoutpeUier (1912), Nos. 1-3, pp. 12-7. 



