217 



house to another, especially if they are far removed from one 

 another. The method of infection may be either by direct 

 pimctnre or by scratching- the skin with fingers contaminated 

 with the blood of a crushed, virus-carrying- bug. The experi- 

 ments of Howard and Clark are regarded by the authors as only 

 proving that the bugs may carry the virus for several days, 

 but do not explain by what means the insect can propagate the 

 disease. The authors made numerous experiments with bug's 

 which had bitten patients suffering- from the disease and report 

 that all were negative, and they found it impossible to discover 

 the virus of infantile paralysis in many specimens of bugs which 

 had certainly bitten patients suffering from typical and well 

 developed poliomyelitis. They are therefore not inclined to 

 favour the idea that bugs do transmit the disease. 



(3) Lice and Fleas. — Howard and Clark obtained negative 

 results with lice, and the authors say that they themselves have 

 been unable to experiment in this direction from want of 

 material. They remark, as against the carriage of the poison by 

 these parasites,"^ that poliomyelitis may claim numerous victims 

 in one family in spite of the total absence of lice; and as to fleas, 

 the experiments of Howard and Clark, Kliug. Petersson and 

 Wernstedt were entirely negative. 



(4) Stomoxys calcitrans. — A brief summary is giveii of the 

 results obtained in America in the transmission of infantile 

 paralysis by means of Stomoxys. The authors say that their own 

 investigations into an epidemic of poliomyelitis at Djurso showed 

 that Stomoxys was absent, and that in another place only a few 

 of these flies were found and those in a stable at a considerable 

 distance from the house in which the patients lived. Further, 

 the particular flies were so feeble in consequence of the lateness 

 of the season, that the possibility of their flight from the stable to 

 the house was hardly credible ; but in spite of this general absence 

 of Stomoxys in this and other places, the disease progressed long 

 after snow had fallen and the local conditions were utterly 

 unfavourable not only to Stomoxys but to all other insects. 



In spite of these general reasons for doubting the transmission 

 of poliomyelitis by Stomoxys, the authors made direct experi- 

 ments on a large number of living Stomoxys wliich were found 

 in the stable above mentioned by injecting the emulsion prepared 

 from them into the brain and peritoneal cavity of a monkey. 

 The result was negative. They regret that, in spite of the 

 general prevalence of the disease, they were only able to make 

 one such experiment in consequence of the absence of the fly, 

 and they revert to their original conclusion that the experiments 

 of others only prove that it is possible for the virus to be pre- 

 served in the bodies of Stomoxys calcitrans for a relatively short 

 time They draw attention to the fact that although the epi- 

 demic reached its maximum during summer and autumn, it 

 continued to rage all through the early months of winter, when 

 biting insects are either excessively rare or entirely absent. _ If 

 insect bites be the cause of the transmission of the virus it is 

 necessary to admit the existence of an extraordinary long incuba- 



