ETIOLOGICAL MOMENT OP AMERICAN SWINE PLAGUE. 133 
The peculiar differentiation of this organism into refracting 
and non-refracting substances, said substances representing also a 
coloring and non-coloring material when properly tested, as well 
as its varied and peculiar biological modifications, have probably 
been the reason that this micro-organism has not been more accu¬ 
rately studied and described by previous investigators, especially 
by Dr. Detmers. These conditions demand the utmost consider¬ 
ation as well as most exact and delicate technique in studying 
their presence and location in tissues. They collect in large num¬ 
bers in the capillaries, especially in those of the lungs and kid¬ 
neys. The utmost precaution is necessary in the discolorization 
of tissues, The “ Gramm method ” applies well to them, but they 
can be colored equally well without it; twenty-four hours’ ex¬ 
posure is necessary in order to obtain satisfactory results. But 
whatever is done, it will only be under very favorable circum¬ 
stances and in the thinnest of sections and after the most artistic 
treatment one can find them in tissues where the full differentia¬ 
tion of their plasma can be distinctly seen. It can be done in 
every organ, but requires time and patience. In thick sections, 
or even in thin ones, the commonly seen object will be a coccus; 
if the section is not stained with some contrast color, the tissues 
themselves, being discolored, will interfere with one’s seeing the 
uncolored middle piece, and the same is true of the contrast col¬ 
ored specimen, unless the organism is in a very thin section, and 
near its upper surface, and then lies transverse to the observer’s 
eye ; if end on, they appear as cocci; if oblique, the lower end is 
not seen, and a coccoid object only is visible. 
In my full and final report to the Board of Regents, these 
conditions will be discussed in detail and fully illustrated by 
drawings from microscopical specimens. 
As one of the purposes of this paper is to endeavor to place 
this organism into the class of Koch’s “ bacteria,” as opposed to 
the latest views of Hueppe, I desire to call attention to two other 
organisms which I have come across in two entirely different 
diseases. 
The first of these micro-organisms was found in the organs of 
the cattle killed by my orders in connection with the singular out- 
