172 THE MICHIGAN ACADEMY OF SCIENCE. 



the medium. The milk gradually clears from above downward, assum- 

 ing a brownish purple color, while a compact, whitish sediment (casein) 

 occupies the bottom of the tube. The clarification begins to appear only 

 after the culture is several weeks old, and then progresses slowly. 



To test the diastatic action of the organism, cultures were made in a 

 medium employed by Foulerton and Jones, consisting of 1 g. of potato 

 starch, 1 g. of pepton, and 0.6 g. of NaCl, in 100 c.c. of distilled water. 

 Foulerton and Jones state, in their work which embodies a quite com- 

 prehensive study of the genus streptothrix, that of all the pathogens (10 

 in number) investigated by them, no one inverts starch. At the end 

 of one week's growth, the addition of iodine to cultures of our organism 

 in this medium shows a comi)]ete inversion of the starch, whereas un- 

 inoculated control tubes still respond to the addition of iodine with a 

 deep blue color. The growth in this mediurii is slight, indicating the 

 production of a strong diastatic ferment. 



Intraperitoneal and subcutaneous injections into guinea-pigs of i/o c.c. 

 each of a rich beef-tea suspension of an agar growth of this organism, 

 have thus far (24 days) been without effect, as have subcutaneous, in- 

 traperitoneal and intrapleural inoculations of similar doses into white 

 rats (13 days). Actinomycotic lesions may exist in the animals, al- 

 though as vet no evidence of such can be detected. It is a well known 

 fact that organisms of the genus streptothrix lose their virulence readily 

 on successive generations in artificial culture. Furthermore, the organ- 

 ism, although pathogenic for man, may be without effect on laboratory 

 aninmls, while therefore the production of disease or death in the in- 

 oculated animals would establish the pathogenicity of the organism, nega- 

 tive results do not prove the contrary. 



My thanks are due to Professor Novy, not only for the privilege of 

 working out the characteristics of this organism, but also for the many 

 suggestions made by him. 

 DAvm J. Levy^ a. B., 



Assistant in Bacteriology. 



Late Scholar of the Rockefeller Institute for Medical Research. 

 From the Hygienic Laboratory, University of Michigan, 

 Ann Arbor. 



