562 A Filter-passing Virus in Certain Diseases [May 30, 



of the most important. Many of these diseases are those most 

 dreaded, and are answerable for the heavy mortality of the young 

 that we still suffer from. It was not possible, working as we did 

 under the conditions obtaining with an army in the field, to do more 

 than to ])egin this work, which it is lioped to carry farther in London 

 in the immediate future. In the following diseases, amongst others, 

 successful preliminary results have been obtained : mumps, rose 

 measles, measles, scarlet fever, and typhus. In all of these filter- 

 passing organisms have been successfully grown in culture and in 

 subculture, but no experimental work proving that these organisms 

 were the actual cause of the diseases in question has been possible as 

 yet, but this it is hoped will soon be carried out. 



In conclusion, some other facts of interest as to the mode of 

 conveyance of some of the diseases dealt with here may be mentioned. 

 The filter-passing virus of some of these diseases is unquestionably 

 conveyed from the sick to the healthy through the agency of insects. 

 This has been definitely proved to be the case in trench fever through 

 the agency of the louse. Typhus is also conveyed by this insect. 



Although the actual virus of yellow fever is unknown, unless 

 Noguchi's recent work has solved the problem, yet there is distinct 

 evidence that this disease is due to a filter-passer, and it is certainly 

 conveyed by a mosquito. 



In rabies the virus is conveyed directly by the Ijite of the rabid 

 animal inoculating the victim with the saliva, and this has long 

 been known to contain the virus, and now the virus can be grown 

 by culture from the salivary glands. 



In influenza the virus would seem to be conveyed directly from 

 tlie sick to the healthy, and further, there is experimental evidence 

 that the filter-passing virus can remain for long periods — e.g. months 

 — -in the tissues of an animal after experimental inoculation with 

 the culture. 



In poliomyelitis there is some dispute as to whether an insect 

 agency plays any part, or whether the transmission is direct from the 

 infected to the healthy. 



In encephalitis, polyneuritis and nephritis the mode of convey- 

 ance of the virus is unknown. 



[J. R. B.] 



