648 SUMMARY OF CURRENT RESEARCHES RELATING TO 



very frequently to epizootic disease. H. Home, who has investigated 

 this " Lemming pest," finds that it is a septicemic condition caused by 

 a streptococcus, which is very highly virulent to guinea-pigs. This 

 organism does not adapt itself readily to existence upon artificial 

 media, and loses its virulence rapidly under such conditions. 



Bacillus Meg'atherium.'* — J. C. Johnson has made a study of the 

 morphology and of the cultural reactions of this organism. He 

 describes it as a motile endosporous bacillus with a length of 5-10 /x 

 and an average diameter of 1 • 2 /x. In liroth cultures there is a 

 tendency to chain formation. Spores formed readily, and numbers of 

 these massed together form a pseudoglcea. The zoogloea formation 

 was not observed. 



For cytological investigations films were fixed with formalin or 

 osmic acid, and treated for 24 hours with Tellyesuiczky's solution. 

 Suitable staining shows a cytoplasm, hyaline in young organisms, 

 granular in more mature forms, a nucleus and a capsule. 



The bacillus grows well upon ordinary media. It liquefies gelatin, 

 and in litmus-gelatin causes 1)leaching in the deeper parts of the 

 medium. Indol is not formed in broth cultures. In silica jelly, a 

 perfectly inorganic medium, no growth occurs. The organism is an 

 obligatory aerobe. It reduces nitrates to ammonia, but cannot produce 

 nitrates from nitrites. It produces invertase and a diastatic ferment. 

 It is not pathogenic. 



Epizootic Lymphangitis.f — J. Bridre, L. Negre, and G. Trouette 

 have made a study of this disease, which prevails among horses and 

 mules in Algeria. Gryptococcus farciminosus, the causal organism, was 

 discovered by Rivolta. After a consideration of the clinical features 

 and morbid changes presented by this disease, the authors describe 

 their observations of this organism. Its morphology and mode of 

 reproduction indicate that it should be placed among the Blastomycetes. 

 Complement deviation experiments indicate a close analogy between 

 this organism aud certain yeasts. It is probable that the disease is 

 transmitted by direct inoculation. 



Effect of Continuous and Alternate Croppings upon Soil 

 Bacteria. I — P. E. Brown has found that the rotation of crops causes 

 the development of greater numbers of organisms in the soil, and of 

 greater ammonifying, nitrifying, and nitrogen-fixing power by the soil, 

 than continuous cropping. He compares the effects of various alterna- 

 tions, and of clover crops turned under as green manure. The use of a 

 green manure in a two-year rotation did not always increase the number 

 of bacteria or the ammonifying, nitrifying, and nitrogen-fixing powers. 

 It appeared that the crop present was more important from the bacterial 

 point of view than the previous cropping. Bacterial activities and 

 crop production are very closely related. 



* Centralbl. Bakt., 2te Abt., xxxv. (1912) pp. 209-22. 



t Ann. Inst. Pasteur, xxvi. (1912) pp. 701-26. 



X Centralbl. Bakt., 2te Abt., xxxv. (1912) pp. 248-72. 



