PSYCHE. 



MOSQUITOES CONSIDERED AS TRANSMITTERS OF YELLOW FEVER 

 AND MALARIA. 



BY CHARLES J. FINLAV, M.D., HAVANA. 



(From the N. V. Medical Record of M.iy 27, iSgg.) 



The tlespised mosquito, denounced 

 by me since iSSi as the agent of trans- 

 mission of 3'ellow fever, is now attract- 

 ing considerable attention among dis- 

 tinguished and sagacious observers wlio 

 attribute to that insect an important rOle 

 in tl^ie etiology and propagation of the 

 malaria infection. To those who are 

 familiar with the biological conditions 

 and the habits of the mosquito, this will 

 not be a matter for surprise ; rather 

 should we wonder how, considering the 

 special aptitudes of the insect, other in- 

 oculable diseases are not ecjually trans- 

 mitted by it, especially such as are due 

 to germs in the blood or in the tissues 

 that lie within reach of its sting. Much 

 light, however, has been thrown upon 

 this singular eclecticism by modern 

 ideas concerning the process by which 

 some blood-sucking insects convey cer- 

 tain diseases, to warm-blooded animals. 

 We are induced by them to i-egard as 

 one of the essential conditions that the 

 transmitting insect should itself experi- 

 ence a true infection, which may not 

 endanger its life nor greatly disturb its 

 physiological functions, but must always 



requiie, on the part of the insect, patho- 

 genous susceptibility for the specific 

 germs which it is called upon to trans- 

 mit. It will thus be readily understood 

 why the same insect may transmit only 

 certain germs and not others, as also 

 that, among insects of the same kind, 

 some species may possess that faculty 

 while others do not. 



Among the publications that have 

 api)eared concerning the transmission 

 of malaria li}' mosquitoes, the most im- 

 portant one, and that which has caused 

 most sensation, has been the lecture de- 

 livered, a few months ago, by Robert 

 Koch, in which he declares himself 

 decidedly in favor of the mosquito 

 theory as the one which most plausibly 

 accounts for the propagation of the. said 

 disease. In support of his idea he cites 

 a very appropriate precedent, the Texas 

 fever, a cattle disease, the etiology and 

 propagation of which were .so ably 

 cler.red up in 1S92 by Dr. Theobald 

 Smith, chief of the division of animal 

 pathology in the Bureau of Animal In- 

 dustry, United States of America. Dr. 

 Smith proved tliat the germ of the 



