3i8 Veterinary Medicine. 



The infecting microbe is not definitely known. Nosotti found 

 a micrococcus in the lymph of the vesicle, which stained readily 

 in aniline colors, was easily cultivated and pathogenic. Klein 

 found a streptococcus which, similarly tested, presented an equal 

 claim to be the causative factor. Bassianus and Siegel found in 

 the blood and tissues of a person who died of foot and mouth 

 disease a small oval bacillus, which they later obtained from the 

 vesicles of three children who were suffering from the disease, 

 and from animals attacked in two successive epizootics. With 

 this they first successfully inoculated a calf and from the pure 

 cultures obtained from its blood, inoculated three calves and a 

 young pig. 



I<6ffl.er and Frosch, the recent commission on foot and mouth 

 disease in Germany, report that no organisms could be seen nor 

 cultivated from the lymph found in recent bullae of the buccal 

 mucosa, though this lymph proved virulent when inoculated on 

 calves. 



They found that the lymph became inert when dried for 24 

 hours at 31° C. (88° F.), while it retained its vitality and viru- 

 lence after exposure for 9 months to a temperature of 0° C. They 

 concluded that it could not penetrate through the unbroken skin 

 nor mucosa, and that it was most effective when injected into the 

 blood or peritoneal cavity. One attack conferred immunity for 5 

 months. Blood from immune animals, injected into susceptible 

 ones, does not confer immunity, but 75 per cent, could be ren- 

 dered immune if injected with a mixture of the lymph from the 

 vesicle and double the same amount of the blood from the immune 

 animal. Animals .so treated become immune to 100 times the 

 infecting dose. Filtered lymph was still virulent and the com- 

 mission suggests that the microbe may be so small as to pass 

 through the filter, and escape discovery by the most powerful 

 lenses. An object one-fifth the size of the smallest known bacil- 

 lus—that of influenza — would be invisible under our best micro- 

 scope. 



By actual experiment the virus has been found in the nose,' 

 larynx, bronchia, stomach and intestines, but into all these the 

 virulent lymph of the bullse can find its way. In the intestineSj 

 indeed, in cases causfed by feeding, bullae have been found on the 

 mucosa. 



