8 BULLETIN 65, U. S. DEPARTMENT OF AGRICULTURE. 
On account of this very old and very plausible theory so often 
advanced, that the disease is due to toxic substances existing in 
damaged grain and fodder, a number of species of fungi were isolated 
during the past year from damaged corn and forage and grown on a 
sterilized corn medium or alfalfa infusion in an effort to produce some 
toxic substance that would create disease when fed to horses. The 
pure cultures were allowed to grow for periods of one month’s dura- 
tion, in flasks containing 250 cubic centimeters of the nutrient 
medium, and the contents of one flask were fed each day for periods 
of 30 days, along with a sufficient quantity of sound corn and hay to 
make a normal ration; but no symptoms have thus far developed 
in the experiment animals, although only about one-half of the number 
of pure cultures isolated have thus far been used in this experiment. 
It is possible that laboratory conditions alone can not be made to 
parallel sufficiently close those which exist naturally in the growing 
plants, and that toxic substances which might be produced in a 
natural state would not be generated in a corn-meal medium in the 
laboratory. The by-products of the growth of both fungi and bacteria 
on corn and forage should certainly receive more consideration in 
future work. In view of the above information it must appear to 
the unbiased mind that the cause of forage poisoning remains an 
obscure and puzzling problem. 
OCCURRENCE. 
Like cerebrospinal meningitis of man, forage poisoning occurs in 
sporadic as well as enzootic and epizootic forms. The sporadic 
cases occur either in different localities from the epizootic out- 
breaks or in such sparse numbers as not to amount to an enzootic. 
Thus the outbreaks are quite variable in extent and severity. Some- 
times they become very widespread, causing heavy losses, as in the 
recent outbreak in Kansas and Nebraska, while at other times there 
are only sporadic cases. Liebener believes that the development of 
the cause of the disease in Germany is favored by the rainfalls and 
warmth of the earth during summer and autumn. No conclusive 
evidence has ever been presented to indicate that the disease is ever 
transmitted directly from one horse to another. Sick animals have 
been placed alongside of susceptible horses in the same stable without 
conveying the disease to the latter, and healthy horses have been 
placed in stalls previously occupied by animals which died of the 
disease, and have eaten from the same mangers without previous 
disinfection, but in no case has the disease been transmitted in this 
manner. In the recent outbreak in Kansas it was quite noticeable 
that livery and other work horses were not affected so long as they 
were fed on clean, dry forage, although they were constantly exposed 
