ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 469 



bacterium assisting the formation of slime, also assists fixation. The 

 author found it was a matter of indiiference whether the medium is acid 

 or alkaline. All bacterial slimes are nitrogenous, and contain soluble 

 albumenoids. There is a symbiosis between the bacterium and the 

 plant. The plant supplies saline and saccharine matters, the latter of 

 which the bacterium converts into gum, and at the same time elaborates 

 atmospheric nitrogen into constituents that are contained partly within 

 the bacterial cell and partly in the gum, which by virtue of their presence 

 appears as a slime. The nitrogenous and carbohydrate constituents of 

 the slime are elaborated by the plant-cells into tissue elements. 



Leptothrix racemosa.* — F. Vicentini describes the morphology of 

 this organism. It occurs on the teeth, and consists of two main portions, 

 a lower felty or alga-like base, and an upper fungoid layer carrying aerial 

 hyphffi with " fruitful heads." The author infers that the organism is 

 of the nature of a lichen, though he classes it among the higher bacteria. 

 It possesses the property of fragmenting into small particles, and the 

 author suggests that Leptothrix racemosa is the parent of all mouth 

 bacteria. 



Tick Fever .f — C. Levaditi and J. Roche, studying the mechanism of 

 the crisis of tick fever which occurs on the 4th-5th day after peritoneal 

 inoculation of the virus, find that the destruction of the spirilla does not 

 depend on bacteriolysins, or on opsonic qualities of the serum, which 

 properties only appear after the disappearance of the spirilla, and seem 

 to be the consequence rather than the cause of their destruction. It was 

 not possible to determine in what form the parasite persisted during the 

 resting phase ; microscopic examination was negative, but mice inoculated 

 with heart-blood and with emulsions of various organs all became 

 affected. 



The authors showed that anti-bodies, spirillolysins, and thermostable 

 opsonins appeared in the blood 16-4H hours after the crisis ; these bodies 

 acted on the spirilla in vitro, rendering them immobile and agglutinated, 

 transforming them into granules, and making them more ready to be 

 phagocyted. But with the relapse of the fever, living and virulent spirilla 

 are present. This research showed that whereas the anti-bodies persist 

 without modification, the spirilla have been subjected to change which 

 enables them to resist the bacteriolytic and opsonic activity of these 

 anti-bodies ; so that the successive reproduction of the treponema is 

 probably due not to the temporary disappearance of the anti-body, but 

 to the immunisation of the parasites against the anti-body. 



Opsonic Properties of Normal and Specific Serums. | — C. Levaditi 

 and Inmann find that the opsonic power of normal serums is due to the 

 intervention of the complement, and slightly also to that of the ambo- 

 ceptor normally contained in these serums. The authors refer to the 

 fact that the aqueous humour of a rabbit, from a first puncture of the 

 anterior chamber, has no opsonic power, does not coagulate, and shows 

 no figured elements, whereas the humour that forms 2-3 hours after- 



• Dental Era, y.-vi. (1906) p. 617 ; and 1907, p. 1. 

 t C.R. Soc. Biol. Paris, Ixii. (1907) pp. 619 and 815. 

 X Tom. cit., pp. 683-869. 



