ZOOLOGY AND BOTAXY, MICROSCOPY, ETC. 343 



flagellum. The vegetative form possesses a distinct nucleus, which 

 disappears, however, in the pre-sporing period, being replaced by a 

 chromatin network, spreading throughout the organism and concentrated 

 upon four highly refractile granules. The sarcina forms of Beijerinck 

 recall in every respect the endospores of certain other bacteria. 



New Achromatic Sulphur Bacteria.* — By cultivations from sea- 

 water and seaweed obtained in the harbour of Trieste, H. Molisch has 

 isolated the following types, hitherto undescribed. Thiothrix annulata 

 consists of numerous threads of considerable length, showing small 

 sulphur granules and marked at intervals with rings, where the filament 

 may reach a width of 5 /x. The width of the remainder of the filament 

 varies from 2 /u, at the ends to ;:5-4 yx in the middle. T. marina, a 

 very common type, shows short slender threads. Beggiatoa marina 

 has threads 2-4 /a in thickness, and on an average 290-350 /x in length. 

 Some threads may attain a length of 2000 (jl. Bacterium bovista, 

 Bacillus fhiogenus, and Spirillum bipunctatum are other forms described 

 by the author. Together with these marine sulphur bacteria is found 

 frequently an organism which has received the name Ghlamydothrix 

 longissima. This occurs in non-motile threads, wliich may attain a 

 length of J cm., provided with delicate sheaths, not visible on direct 

 examination. Spirillum granulatuni, a fresh-water form, the largest 

 sulphur bacterium hitherto described, is a stout spirillum, provided with 

 two flagella. 



Organism Intermediate between Typhoid and Paratyphoid 

 Bacillus. t — In the course of an investigation of certain cases of enteric 

 fever in Algeria, M. Raynaud and L. Negre have encountered an 

 organism which possesses characters intermediate between those of 

 B. typhosus and those of B.paratgphosiis A. This bacillus is smaller 

 and less motile than Eberth's bacillus ; its colonies upon agar are larger 

 and more opaque. It ferments glucose, Iffivulose, and mannite, and fails 

 to clot milk. Neutral red is partly decolorized. It is agglutinated 

 alike by typhoid and paratyphoid A serum in a dilution of 1 : 5000. 

 Paratyphoid B serum causes no agglutination. It is less virulent for 

 mice than the typhoid bacillus. 



New Iron Bacterium. | — H. Schwers gives an account oi Megalothrix 

 discophora, a new type of iron bacterium, isolated from iron and 

 manganous streams in many districts of Germany and Central Europe. 

 This organism grows in large filaments surrounded by a broad homo- 

 geneous grey or pale-yellow sheath, while a fine canal runs through the 

 filament. Dichotomy was observed rarely. Owing to the thickness of 

 the sheath, it was not easy to discover the division of the filaments into 

 long cells. The size of the filaments and the nature of the sheath 

 constitute generic differences between this bacterium and such types as 

 Leptothrix, Crenothrix, or Cldamydotlirix. 



* Centralbl. Bakt., 2te Abt., xxxiii. (1912) pp. 55-62. 



t C.R. Soc. Biol. Paris, Ixxii. (1912) pp. 534-5. 



X Centralbl. Bakt., 2te Abt., xxxiii. (1912) pp. 273-6. 



