ETIOLOGICAL MOMENT IN AMERICAN SWINE PLAGUE. 127 
different media have their essential biological phenomena, in that 
the cultivations frequently assume certain characteristic forms in 
some special medium. 
The condition of biological research, with regard to the 
pathogenetic micro-organisms, is fast getting so contradictory that 
investigators will soon have to come to some definite understand¬ 
ing as to the technical meaning of words in order to understand 
one another. In no sense is this fact so apparent as in regard to 
the oval organisms which seem to belong to the class of diseases 
which will eventually be known as the infectious septicaemia. 
Koch has given the name “ bacteria ” to this class to distin¬ 
guish them from the absolutely round organisms, micrococci, 
which color homogeneously, and the rod and twisted organisms. 
It is greatly to be regretted that Hueppe has lately thrown the 
whole question into chaotic confusion by classing everything but 
the various straight and twisted rods or threads as “ micrococci,” 
which should never be accepted or brought into general use. 
The micro-organism of the true American swine plague is, 
then, a bacterium in its mature form. It is not a micrococcus. 
It is oval, being at least twice as long as wide when fully de¬ 
veloped, its length as a mature individual being about one-half 
the diameter of the red blood cell of a hog when examined in 
freshly drawn blood under the microscope and care is taken that 
no atmospheric or chemical influences interfere with the mor¬ 
phology of the blood cell. 
It colors best in methylen-blue and methyl-violet, next best in 
gentian-violet and methylen-green, also very well in the other 
violets, especially in a variety known as Hoffs violet but not as 
well as many other organisms in fuchsin. As has been pointed 
out by Loeffler and others in Germany, the coloring capacity of 
many of these dyes is increased by adding to saturated solutions 
of the same in the coloring glass an equal quantity of a solution 
of caustic potash 1-10,000 aqua. 
The same must be fitted every time before using. 
In coloring this organism the result will somewhat depend 
upon the length of time the covering glass specimen is exposed 
to the action of the coloring material, and the same is true with 
