28 (92) Society for Experimental Biology and Medicine. 



such cytozoa may contain no trypanosomes. Thus, cultures 

 attempted from twenty-six of such heavily infected birds failed to 

 show any growth. Again, the presence of trypanosomes is not 

 associated with any one form of intracellular parasite. Further- 

 more, the cultural method shows the existence of several distinct 

 species of trypanosomes, and among these is one which presents 

 at the same time both types described by Schaudinn as stages on 

 the one hand for halteridium and on the other hand for the " leuco- 

 cytozoon " of Danilewsky. 



The authors therefore conclude that trypanosomes in birds 

 may be met with as several distinct species wholly unrelated to 

 the intracellular parasites. The greatly diverging conclusions 

 reached by Schaudinn and the authors must be ascribed to the 

 fact that Schaudinn worked with mixed cultures as developed in 

 the body of the mosquito, whereas the authors have employed 

 strictly pure cultures of these flagellates. 



[The authors published the full details of a part of this investi- 

 gation in the March issue (1905) of the Journal of Infectious Dis- 

 eases. Additional papers will appear in later issues.] 



5 (51). " The gradual decrease in bacteria of the production of 

 agglutinable substance ": WILLIAM H. PARK. 



At the last meeting of the Society of American Pathologists 

 and Bacteriologists an informal statement of this fact was made 

 by Dr. Welch for Drs. Marshall and Knox. The experiments of 

 Dr. Collins and the author are reported here because they were 

 undertaken in a slightly different way and also because a certain 

 number of confirmatory observations are of value. 



The maltose-fermenting paradysentery bacillus of Flexner was 

 grown for twenty-four hours on each of eleven consecutive days 

 in fresh bouillon solutions of the serum from a horse immunized 

 through oft-repeated injections of the bacillus. The serum 

 strength in the solutions used was 1.5^, 4ft and 15^. The 

 serum agglutinated the culture before its growth in the solutions 

 in dilutions up to 1 in 800, and was strongly bactericidal in ani- 

 mals. After eleven transfers the culture grown in the 15^0 solu- 

 tion ceased to be distinctly agglutinated by the scrum in any 

 dilution and ceased to absorb from the serum any appreciable 

 amount of the agglutinins acting upon the original culture. The 



