experiments of Loeffier & Frosch in 1898 have shown that the virus 
will pass through the finest Chamberland filter, thus indicating its 
ultramicroscopic size and the reason it has not been detected by 
staining methods. They inoculated experiment animals with this 
filtrate free from all indications of bacterial growth and transmitted 
the disease through a series of animals. These results have since been 
confirruecl by other investigators. Observations which have been made 
upon the viability of this filterable virus led to the conclusion that 
the contagion is quite readily destroyed, and milk which has been 
pasteurized for the elimination of tubercle and typhoid bacilli will 
not prove capable of transmitting the disease to persons or animals 
fed with it. Experiments which have been made in recent years 
proved that the contagion will lose its virulence after fifteen minutes 
exposure at 50° C.. by being heated for ten minutes at 70° C., while 
exposure to 100° C. destroys it at once. 
The following disinfectants will destroy the virus in one hour: 
Ordinary whitewash: 1 per cent solution of carbolic acid: 3 per cent 
solution of soda, and 1 per cent solution of muriatic acid. 
On the other hand, the resistance of the virus to the influence of 
low temperatures is quite marked, and the infected lymph will retain 
its activity for at least a month when placed in a refrigerator, while 
exposure to a temperature of minus 48° C. for about three hours 
did not destroy its virulence. Infectious milk three or four days 
old, after having turned sour, or milk to which rennet has been added, 
is not capable of transmitting the contagion In fresh cattle or 
swine manure the infectious material is very soon destroyod at a 
depth of over 1 foot, owing to the heat developing therein in conse- 
quence of decomposition and reaching about 70° C. 
The experiments which have been made in Denmark and Germany 
indicate that the form of pasteurization recommended in article 20 
of this bulletin is undoubtedly sufficient to kill the infectious prin- 
ciple of foot-and-mouth disease. 
ACTINOMYCOSIS. 
This disease, while not at all infrequent in the maxillary regions of 
cattle, is qjiite rarely located in the udder. It is readily mistaken 
for tuberculosis, owing to the diffuse lesions and the character of the 
pus. TVkile no known case of actinomycosis in man has been traced 
to the milk, it is nevertheless advisable to condemn the milk from 
an infected udder, especially since the virus of the disease in man, in 
most cases, has been found to enter the body through the alimentary 
canal. Furthermore, there is usually in actinomycosis a mixed in- 
fection with pus-producing cocci, which emphasizes the necessity for 
prohibiting the use of the milk from such udders. 
