254 CONTAGIOUS DISEASES OF DOMESTICATED ANIMALS. 



southern cattle fever may be entirely diflerent in their behavior from 

 any other known species of pathogenic micrococci. There are, how- 

 ever, some other facts which tend to show that the bacilli and not the 

 micrococci most likely constitute the pathogenic principle. 



1. The bacilli are a constant occurrence in the diseased parts, but par- 

 ticularly in the liver aud in the spleen of cattle that are affected with 

 or have died of southern cattle fever. 



2. The bacilli sufficiently differ in shape and size from all other well- 

 known species to be at one recognized when seen under a sufficiently 

 high power, a fact which I intend to demonstrate, not by a description 

 or by drawing, but by photo-micrographs, as soon as I shall be able to 

 obtain fresh material in which the bacilli have not been subjected to any 

 change whatever b^^ the action of hardening fluids or reagents. 



3. In three sections of liver aud spleen recentlj' mounted in balsam, 

 but cut last winter from pieces of liver and spleen which were hard- 

 ened thirteen months ago, when perfectly fresh, in alcohol and in a 

 a solution of bichromate of potash, and have since been preserved in 

 alcohol, the bacilli are yet intact, and under a high power homogeneous 

 immersion objective are easily recognized as the same kind of bacilli 

 which I never failed to And in the diseased livers aud spleens when exam- 

 ined fresh. Besides, the bacilli do not merely adhere to the surface of 

 the sections, but appear to be imbedded in the tissue, because they are 

 found at different depths, and require to be seen under a high power 

 and different focusing, according to the plane in which they lie. The 

 sections, when cut last winter, were stained in " Beale's carmine," and 

 before being mounted Avere restained in an aqueous solution of methyl- 

 violet (1:500), but after they had been in alcohol and oil of cloves, and 

 been mounted, the aniline staining had almost entirely disappeared, 

 been washed out by the alcohol and oil of cloves, and thus the 

 bacilli, which did not take the carmine stain, appear but indifferently 

 stained with methyl violet, and are rather pale, but are plainly seen 

 aud easily recognized. 



4. The micrococci or diplococci that may have been present in the 

 liver and spleen are nowabsent^at least cannot be found notwithstand- 

 ing a most careful search, which proves to me that the same, if they 

 have been present in those tisssues, must have been there by accident, 

 or have existed only in the fluids, and have never been imbedded in the 

 solids like the bacilli. In my opinion the facts just related plainly show 

 that the presence of the bacilli cannot be an accident, but must have 

 some connection with the morbid process. 



Last year, when investigating the southern cattle fever in the South- 

 west, and even before, when I made my flrst observations on that disease 

 and several ^ost-wior<ew examinations of cattle that had died in Cham- 

 paign, I became fully convinced that I had to deal with a bacteritic 

 disease, or with a disease that owes its existence to some ])athogeni(; 

 bacterium. As it is admitted that the southern cattle fever has its 



