194 Psyche [December 



by bringing an emulsion of a known virus obtained from human 

 sources in direct association with the central nervous system. 

 After the flies had had abundant opportunity to bite these in- 

 fected monkeys during the various stages of the disease, including 

 the period of incubation, healthy monkeys were then exposed to 

 the bites of these same flies. Of 12 healthy monkeys indications 

 of the disease have been obtained in 6, 3 of them in a virulent 

 form, resulting in death, the other 3 with transient tremblmgs, 

 partial paralysis, diarrhoea and recovery. It is interesting to note 

 that several of the monkeys had diarrhoea, therein the disease 

 resembles the human disease more closely than when monkeys are 

 simply inoculated with the virus into the brain, for gastro-intestinal 

 upsets in children are frequently associated with infantile paralysis. 



In these experiments it is important, we think, to use the proper 

 technic in order to obtain successful results. The flies should be 

 handled as little as possible. It is much better to handle the mon- 

 keys and leave the flies alone. In our experiment the flies v.ere 

 caught in nature, some of them were bred, placed in a large cage 

 about 6 feet long by 5 or 6 feet wide, and some 3 or 4 feet high. 

 The monkeys are stretched out at full length and wrapped in 

 chicken wire. In this way they can be placed in the cage and the 

 flies have full opportunity to bite. The flies appear to need a 

 feed of blood about every day or two. They sometimes visit 

 water which is kept in the cage, but apparently cannot be in- 

 duced to eat any other food than the blood. At least, in our 

 experiments, bananas, fruits and other substances exposed ap- 

 parently were little visited by the flies. Furthermore, in our 

 experiments a very large number of flies were used. 



In conclusion we desire simply to summarize the fact that we 

 have apparently transferred the virus of poliomyelitis from 

 monkey to monkey through the bite of the stable fly, Stomoxys 

 calcitrans. We would like to emphasize the fact that this does 

 not appear to be simply a mechanical transference, but rather a 

 biological one, requiring a period of extrinsic incubation in the 

 intermediate host. 



What conclusions can we draw from these facts? At present it 

 seems to us we would not be justified in drawing any conclusion 

 — the significance of the facts if confirmed^ is self-evident. 



*As previously noted (p. 191), these experiments have been confirmed by Anderson and Frost. 



