Infantile Paralysis or Acute Anterior Poliomyelitis 245 



spite of these precautions, all their restilts were negative, none of the 

 inoctilated animals having contracted poliomyelitis. They also 

 experimented with bedbugs which had fed upon infected patients at 

 various stages of the disease, but the results in these cases also were 

 wholly negative. 



Kling and Levaditi considered at length the possibility of trans- 

 mission of the disease by Stomoxys. As a result of their epidemiologi- 

 cal studies, they foimd that infantile paralysis continued to spread 

 in epidemic form in the dead of winter, when these flies were very 

 rare and torpid, or were even completely absent. Numerous cases 

 developed in the northern part of Sweden late in October and 

 November, long after snow had fallen. On account of the rarity 

 of the Stomoxys flies during the period of their investigations they 

 were imable to conduct satisfactory experiments. In one instance, 

 dtuing a severe epidemic, they found a number of the flies in a stable 

 near a house inhabited by an infected family, though none was 

 found in the house itself. These flies were used in preparing an 

 emulsion which, after filtering, was injected into the peritoneal 

 cavity of a monkey. The result was wholly negative. 



As for the earlier experiments, Kling and Levaditi believe if the 

 flies were responsible for the transmission of the disease in the cases 

 reported by Rosenau and Brues, and the first experiments of Ander- 

 son and Frost, it was because the virus of infantile paralysis is elimi- 

 nated with the nasal secretions of paralyzed monkeys and the flies, 

 becoming contaminated, had merely acted as accidental carriers. 



Still further evidence against the hypothesis of the transmission 

 of acute anterior poliomyelitis by Stomoxys calcitrans was brought 

 forward by Sawyer and Herms (19 13). Special precautions were 

 used to prevent the transference of saliva or other possibly infectious 

 material from the surface of one monkey to that of another, and to 

 avoid the possibility of complicating the experiments by intro- 

 ducing other pathogenic organisms from wild flies, only laboratory- 

 bred flies were used. In a series of seven carefully performed experi- 

 ments, in which the conditions were varied. Sawyer and Herms were 

 unable to transmit poliomyelitis from monkey to monkey through 

 the agency of Stomoxys, or to obtain any indication that the fly is the 

 usual agent for spreading the disease in nature. 



The evidence at hand to date indicates that acute anterior polio- 

 myelitis, or infantile paralysis, is transmitted by contact with in- 

 fected persons. Under certain conditions insects may be agents in 

 spreading the disease, but their r61e is a subordinate one. 



