ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 109 



plated upon lactose-litmus-agar or upon fuchsin-agar. The author found 

 that these organisms were ofteu recovered from the malachite green plate 

 by this means, when a negative result was obtained from the plates 

 directly inoculated. He emphasized two points : firstly, that the emul- 

 sion on the malachite green plate should not be shaken, as this permits 

 less motile and less easily detached organisms to be taken up ; and, 

 secondly, that the malachite green (Hochst 120) should be fresh or 

 kept in an ice chest. 



The author concludes that this method is a necessary adjunct to the 

 method of simple plating, and gives a better chance of finding the 

 organisms when they are scarce. The greater the bulk of fajces plated, 

 the more valuable the results obtained. 



New Method for Differentiation of Bacteria.* — L. S. Dudgeon, 

 I>. X. Panton, and H. A. F. Wilson have made a series of observations 

 upon the influence of bacterial extracts upon phagocytosis. These 

 extracts were prepared by freezing and thawing alternately thick bacterial 

 pastes, so that the organisms became disintegrated. By dividing phago- 

 cytosis experiments into stages and, in the first place, incubating extract 

 and leucocytes, extract and bacteria, or extract and serum, and then 

 adding the third component and again incubating, it was shown that the 

 specific action of the extract was upon the serum ; but it was also found 

 that this action was not directly related to absorption of complement. 

 The diagnostic value rests upon the observation that an extract will 

 remove from a serum with which it has been incubated almost all the 

 homologous opsonin. Thus if serum after incubation with typhoid 

 extract lie added to leucocytes and typhoid bacilli and incubated, no 

 phagocytosis will occur ; while, on the other hand, phagocytosis of 

 another organism, such as Bacillus achard, i not much diminished. 



Rapid Method of Identifying Bacillus coli.f— F. Domergue and 

 R. Legendres give an account of their method for determining the 

 presence of this organism in samples of water or shellfish. Tubes of 

 nutrient broth are prepared, and, after sterilization, there are added to 

 each tube fifteen drops of a solution containing 0*5 p.c. of neutral red 

 and 5 p.c. of phenol. The tube is then inoculated with material, and 

 placed within a large thick glass tube containing a few cubic centimetres 

 of water and tablets of caustic soda and pyrogallic acid. The outer tube 

 is now hermetically sealed, and in a few moments oxygen and carbon- 

 dioxide arc completely absorbed. After incubation at 12° C. for 21 or 

 48 hours the culture is examined, and the presence of Barillas coli is 

 indicated by the canary-yellow colour of the medium, green fluorescence, 

 and the production on the surface of gas-bubbles. The high incubation 

 temperature and the anaerobiosis are important agencies for the selection 



Of B. roll. 



(2) Preparing Objects- 

 Examining the Salivary Glands of Ticks. i — M. Elmassian dissected 

 out the salivary glands in saline water by Christophers' method and then 



* Proc. Roy. Soc, lxxxiii. B (1910) pp. 33-7. 

 t Comptes'Rendus, cli. (1910) pp. 1401-3. 

 , X Arch. Zool. Exper. et Gen., xlv. (1910) pp. 379-419 (2 pis). 



