MUMPS 265 



after the appearance of the eruption. It resists drying and freez- 

 ing. It is destroyed at 55C, in fifteen minutes; it has not been 

 cultivated. Immunity follows an attack but no passive immunity 

 has been reported. 



Mumps. This disease seems also to be due to a filterable virus, 

 resident within the parotid gland, capable of transmission to 

 monkeys. Many organisms have been described but none is 

 probably specific. 



It must be said of both the hypothetical organisms of variola 

 and scarlatina, that if they are the cause of these two diseases 

 they differ from all other known protozoan parasites, because 

 the latter require an intermediate host for the transmission of 

 the parasite from individual to individual while these certainly 

 do not. 



Rocky Mountain Fever is not due to a filterable virus but its 

 agent resides in the blood. It is a disease of the Rocky Mountain 

 States characterized by general pains; macular eruption and con- 

 stitutional symptoms of infection, it is transmitted by means of the 

 tick, Dermacentor venustus. The female tick obtains the agent 

 by blood sucking and can transmit it to her young. The virus 

 is destroyed by heating and drying. A minute coccoid body has 

 been found in the tick but it has not been cultivated. One 

 artificial attack in the guinea pig leaves immunity, as does the 

 spontaneous disease in man. 



Trench Fever is a disease which became known in the Great 

 War characterized by fever, pains in the legs, back and head, with 

 marked dizziness, due to a resistant filterable virus, in all proba- 

 bility transmitted by lice; the virus is found in the blood. The 

 entrance is effected either by the bite of a louse or its f eces may be 

 scratched into tiny wounds on the skin. The virus seems to be 

 excreted in the urine and sputum. It is not killed at 8oC. The 

 louse is not infective for seven days after biting a patient and 

 then remains infective for three weeks. No immunity follows an 

 attack. 



