V 



78 SUMMARY OF CURRENT RESEARCHES RELATING TO 



cilia of a bacterium obtained from a typhoid patient. These compound 

 cilia take the form of relatively immense fusiform spirals surrounding 

 a central substance, the nature of which was not determined. Malvoz 

 supports the view of Migula that these cilia are really compound, and 

 not merely a single cilium of colossal proportions. The mode of forma- 

 tion of the spirals is uncertain, but, in all probability, two bacteria 

 become attached by their cilia, one of the latter becoming separated 

 from its bacterium. The frequent repetition of this process finally 

 results in the formation of the complex spirals, which, breaking away 

 from the bacterium, ultimately lie free in the surrounding liquid. 



Use of Neutral Red in the Study of Phagocytosis, &c* — The 

 ^alue of neutral red as a reagent depends upon its property of staining 

 living cells. J. Himmel finds that the stain is taken up by all substances 

 engulfed in the living leucocyte, and also by the granules resulting 

 from the metabolism of the cell. The staining action depends upon 

 the oxidising properties of the cell, and it is also shown that all factors 

 affecting the vitality of the cell have a corresponding action upon the 

 efficiency of the stain. 



/ Identification of some Anaerobic Bacteria.t — P. Achalme con- 



cludes that form and relative mobility are useless .as criteria for the 

 identification of species. Staining, however, especially by the Claudius 

 method, is of considerable value in the discrimination of different 

 groups of species, but is of little value for the distinction of the species 

 themselves. Again, the appearances presented by cultures upon solid 

 media are of no value, as the appearances depend upon the nature, and 

 especially the consistency of, the medium. The mode of spore-forma- 

 tion is more satisfactory, but is by no means sufficient. Achalme 

 expected to obtain the most reliable results from observations upon 

 the differences, if any, existing between the assimilatory functions of 

 the forms studied, and his expectations were fully realised. He ex- 

 perimented upon nitrogenous and carbohydrate media, the points 

 considered being (1) the means employed by the microbe for the 

 utilisation of the food-substance, (2) the chemical nature of this sub- 

 stance, (3) the nature of the chemical changes brought about in the 

 medium by the organism. Studying more especially (1) the action of 

 the bacteria upon albumen in the presence of different carbohydrates, 

 and (2) the influence of the latter upon the relative abundance of the 

 cultures, Achalme was enabled to construct a dichotomous key for the 

 identification of the species considered, the criteria being as indicated. 



Agglutination.} — Nicolle and Trenel find that the agglutinative 

 and agglutinogenous functions are subject to the greatest variations, 

 and conclude that the functions can be referred to the enveloping 

 membrane of the microbe. This is supported by the fact that the 

 phenomena are much more obvious in those bacteria with the mem- 

 brane well developed than in those in which the membrane is not so 

 obvious. The authors come to the same conclusion in regard to the 

 free cells of the organism. 



* Ann. Inst. Pasteur, xvi. (1902) pp. 663-85. 



t Op. cit., pp. 641-61. X Op. cit., pp. 5G2-86. 



