413 
HOG CHOLERA, OR SWINE PLAGUE. 
— —’- -- - - 
to the eye of the observer; for, in studying its development 
with colored preparations from cultures, under the microscope, 
the observer will often see objects strongly resembling micro¬ 
cocci in appearance; more careful observations, however, will 
show that this is simply a stage in the development of this 
organism, and very careful observation will show that the cocci- 
appearing objects invariably have an ovoid form, though not 
so well marked as in mature bacteria. They proliferate with 
fearful rapidity. The first phenomenon seen is that the object 
increases in length and somewhat in breadth. The uncolored 
substance which appears to be a secretion of the poles, although 
the contrary may be the case, becoming more plentiful; when 
first one and then the other pole end, or colored substance, is 
separated, leaving two of the cocci-like objects as fine bodies in 
the culture ; these are at first small, but rapidly increase in size, 
so that in the same field one has an appearance which would lead 
him to think, in colored specimens, that the culture had become 
polluted, unless he had seen the organism develop under the 
microscope in what is known as a “ hanging drop,” which is pre¬ 
pared as follows : Take an object glass that has a hollow chamber 
ground out of it, surround this chamber with a thin layer of 
vaseline; then take a clean sterilized covering glass and place in 
the middle of it a drop of sterilized beef infusion, or bullion, 
which is inoculated from any culture; the covering glass is now 
to be carefully turned over and placed upon the object glass so 
that the drop is in the middle of the excavation ; it is then to be 
pressed down upon the covering glass, the vaseline making an 
impervious cavity, so that germs from the air cannot get in and 
evaporation does not take place. 
When inoculated in beef infusion gelatine, which is prepared 
as follows: Fresh lean beef, 250 grammes; to this add 500 
grammes of distilled water; place in a cool place for twenty-four 
hours, then strain off until you get 400 grammes of fluid, to 
which add ten per cent, of gelatine of the best quality, one per 
cent, peptone, one-half per cent, cooking salt, cook until the 
albumen is entirely precipitated, then neutralize to a slightly 
alkaline reaction, then strain off into sterilized test-tubes plugged 
