346 Veranus Alva Moore 



the more typical forms of these species.* This would indi- 

 cate that the evolutionarj' theory of Rodet and Roux is as 

 applicable to the hog cholera germ as it is to the typhoid 

 bacillus. Although the development of these specific patho- 

 genic bacteria from a common intestinal germ is improbable, 

 yet the possibility can not be gainsaid and the importance 

 which this theory has in its bearing upon public health, as 

 well as in its relation to pure bacteriology, renders its demon- 

 stration of much interest. This, and many other interesting 

 problems connected with the specific limitations of these bac- 

 teria, emphasize the importance of determining as far as 

 possible the extent to which their flagella may be deemed of 

 differential value. In my efforts to do this, I have considered 

 the flagella not only of the more typical species but also of a 

 considerable number of modified forms (excepting the typhoid 

 bacillus) of these bacteria. From these investigations, I have 

 found their flagella to be much more constant than their bio- 

 logical properties, but contrary to Luksch, I have not found 

 them to be of specific differential importance. The evidence 

 to support this conclusion is found in the subsequent descrip- 

 tion of the character of the flagella. 



I have limited myself to a consideration of a very few of the 

 many interesting questions which have presented themselves 

 in the study of the flagella of these bacteria. A large amount 

 of experimental work was necessary before a satisfactory 

 method for their demonstration could be formulated. This 

 being accomplished the specific objects which I endeavored 

 to attain are : 



I. To complete as far as possible our knowledge of the mor- 

 pholog)^ of each of these organisms. 



*In a communication to the Biological section of the American 

 Association for the advancement of Science, in 1S90 (Nezv Yoi'k 3fed. 

 Journal LII (1890) p. 485). Dr. Theobald Smith described a hog cholera 

 bacillus which was, " in every way nearer the saprophytic forms (coli) 

 than the germ usually found in epizootics of that disease." I have 

 found similar variations in the colon bacteria isolated from variously 

 diseased organs of different animals. In an outbreak of swine disease 

 in 1892, I isolated several colon bacteria which approached in their bio- 

 logical characters very closely to the hog cholera organism. 



