226 
FOOT AND MOUTH DISEASE. 
power of communicating infection to the healthy system 
cannot be distinguished from those which assist in the sup- 
port of the tissues during the process of nutrition. 
Microscopic examinations of the discharge from the eyes, 
the saliva, the contents of vesicles, and also of the milk, have 
resulted in the discovery of very interesting changes in the 
molecular constitution of the several secretions. The saliva 
when carefully collected, without touching the skinor mucous 
membrane of the mouth, is quite pellucid, and contains small 
stellate crystals, and minute spherical bodies (Monads), which 
move w T ith activity in the fluid. In the limpid fluid of the 
vesicles there are large nucleated cells and masses of living 
germinal matter, besides Monads, Bacteria, and Vibriones. 
Similar bodies are found in the fluid discharged from the eye. 
Specimens of milk obtained from cows in various stages of 
the disease have been submitted to microscopic inspection 
repeatedly, for the purpose of ascertaining, if possible, 
whether or not any change occurs in the constitution of the 
fluid likely to be injurious to the health of those who partake 
of it. 
Nearly all the specimens of milk which were tested had a 
low specific gravity (1024), and generally a fair proportion 
of cream was thrown up. There were invariably found large 
granular cells, or white corpuscles having the general 
characters of the pus globule. The milk from one cow was 
examined from the commencement to the termination of the 
disease, and for three weeks after recovery, and it was 
observed that the pus-like bodies remained during the whole 
time. At the worst period of the affection the bodies were 
numerous, and as the disease declined they became fewer in 
number ; but some where seen on the last examination, three 
weeks after recovery. Monads and Bacteria were also 
detected in every specimen, and these bodies remained 
unaffected, either in their form or rapidity of movement, by 
boiling. The specific gravity of the milk was found to rise 
slightly during convalescence from 1024 to 1027, the last 
number being within three or four degrees of the normal 
standard. In two instances the specific gravity of the milk 
was respectively 1032 and 1034, the quantity in each case 
being reduced to one-fifth of the ordinary yield. Milk taken 
in the evening from diseased animals gave evidence of the 
commencement of decomposition on the following morning. 
This was, in some measure, due to the high temperature 
which prevailed during the time the observations were made. 
When boiled, the milk remained good for twenty-four hours, 
under the same circumstances and at the same time. 
