218 HOWARD: CARRIAGE OF DISEASE BY INSECTS 



shown that this organism was carried from southern cattle 

 to non-immune cattle by the so-called southern cattle tick 

 (Mar gar opus annulatus), the results of this experimental work 

 having been published in 1893. 



Even before this, however, Dr. Patrick Manson, now Sir 

 Patrick Manson, had demonstrated the carriage of the parasitic 

 worm, Filaria nocturna, responsible for certain of the diseases 

 grouped under the name filariasis, from mosquitoes to man. 

 Manson' s discovery was, however, by no means so significant 

 as that of Theobald Smith. The announcement of Smith's 

 discovery, however, coming from a veterinary service and 

 published in the annual report of the Department of Agricul- 

 ture, unfortunately received little attention from the scientific 

 world in general. 



The initial discovery which attracted world-wide attention 

 was that of Ronald Ross in India, who found that malaria is 

 carried by certain mosquitoes. 



The speaker here digressed in order to give his views con- 

 cerning the recently agitated theory of the transmission of 

 infantile paralysis by insects. He said: 



The whole country was interested and alarmed at the occurrence of 

 an unusual number of cases of infantile paralysis during the past sum- 

 mer (23,970 in all, with 2072 deaths out of a total of 7925 cases in New 

 York City alone), and many theories were advanced concerning its 

 method of spread. I must confess that when it was announced that 

 the causative organism had been found in the intestinal passages as 

 well as elsewhere and that it probably enters the body of the patient 

 through the mucous membrane of the mouth and nose, I instantly 

 thought of the house fly and the all too frequent contamination of 

 exposed food by this insect, frequently fresh from intestinal discharges. 

 But a second thought showed me that were such a method of convey- 

 ance of the disease possible the disease itself would be much more 

 common and there would have been last summer very many thousands 

 rather than many hundreds of cases. Then too, the not infrequent 

 winter cases could not very well be fly-borne. 



Mosquitoes have been suggested as carriers, and a well reasoned 

 paper by 'Dr. Mark W. Richardson, of Boston, was published last 

 September under the title "The Rat and Infantile Paralysis," the rat- 

 flea of course being the theoretical carrier. But rat-fleas go to human 

 beings only in the event of epidemic disease among rats, and nothing 

 of the sort has been noted in connection with any of the larger epidemics 

 of infantile paralysis. 



