THE FILTERABLE VIRUSES 109 



may be relied upon for disinfection of premises, and should 

 be regarded as preferable to chemical disinfection in the 

 case of large quantities of manure and of premises not 

 readily capable of being disinfected by artificial means. 



Typhus Fever. Hort (Medical Press, October 28, 1914), 

 after filtration of typhus urine through Berkefeld filters, 

 found small cocco-bacillary forms which grew on human 

 blood- agar. He obtained the same organism in cultures 

 from blood and cerebro-spinal fluid, and these cultures 

 produced high continued fever in bonnet monkeys. The 

 small coccal and bacillary forms give place to large coccal 

 and bacillary forms when urine, blood, or cerebro-spinal 

 fluid, is incubated, which forms appear incapable of pro- 

 ducing fever in bonnet monkeys. Hort regards the 

 filter-passing cocco-bacillus as infective, and thinks it 

 probably capable of mutation into the larger cocco- 

 bacillary forms. Sambon found the body louse was the 

 transmitting agent of typhus. 



Measles. The virus appears to be filterable. It may 

 lose its infectivity after fifteen minutes at 55 C., and 

 resist freezing for twenty-five hours (Goldberger and 

 Anderson). These workers and others have shown that the 

 blood and the nasal and oral secretions of patients contain 

 the infective agent from twenty-four hours preceding to 

 twenty-four hours following the appearance of the eruption. 

 Rinderpest (cattle plague) occurs in India and South 

 Africa. The virus is filterable. Sir George Turner 

 stamped out rinderpest in Cape Colony by the simultaneous 

 inoculation with virus and serum. 



Foot-and-Mouth Disease, aphthous fever, or eczema 

 epizootica, is an infectious disease of cattle, characterised 

 by a vesicular eruption of the mouth, teats, and about the 

 feet. It affects also sheep and pigs, and may be com- 

 municated to man by milk or cheese and butter made 

 from it, and usually produces in the human subject an 

 aphthous condition of the mouth. The organism is 

 filterable through a Berkefeld filter. The blood is infective 

 only in the earliest stage of the disease. The virus is 

 present in the contents of the vesicles which contaminate 

 the saliva, litter, milk, etc. The virus is very susceptible 

 to desiccation and light, is killed by a temperature of 

 56 to 70 C., but under natural conditions may remain 

 active for months. Horses, dogs, and cats occasionally 



