PRESIDENT S ADDRESS. XCV 



apartment a few mosquitoes which, twenty days ago, fed on a new 

 case of fever, were set free. In the other apartment was put clothing 

 soiled by Yellow Fever patients. On the 21st of last December the 

 volunteers entered upon their strange preparation for Christmas. On 

 Christinas day, three days and twenty-three hours after being first 

 bitten, John J. Moren took ill with the fever, of which in due time he 

 recovered. Out of seven who attempted to be infected by mosquitoes, 

 only one escaped. Of the seven who were attempted to be infected by 

 the Yellow Fever filth in the other half, all escaped. 



The result of all this was that the regulations for the treatment of 

 Yellow Fever epidemics had to undergo a complete revolution, with 

 the most satisfactory results. It is not found necessary to destroy all 

 the mosquitoes of the species Culax fasciatus, which is the species so 

 far found to be capable of infection. It serves the same purpose to 

 prevent any mosquito from infection by touching a fever patient a 

 regulation which must be as agreeable to the patient as it is useful to 

 the public. 



SHEEP-FLUKE OBJECT LESSON. 



But the mosquito is not the only dangerous carrier of disease. 

 Any fly may carry the germs of disease by simple contact. Some of 

 them may carry special diseases within their bodies, as in the cases 

 discussed. It took a long time before the cause of the spread of the 

 Texas Cattle Fever was discovered to be by infected ticks. But as 

 soon as the discovery was made, the control of the disease was assured. 



Some of the histories of disease carriers are most complicated. 

 And I hope you will pardon me for the reference to one as an illus- 

 tration of the value which may eventually come from our exploring 

 all the corners of our country for the insignificant animals and plants 

 found on the earth or in the water, such work as some members of 

 such societies as ours are always doing, without any immediate indus- 

 trial or significant results. 



In Britain the sheep in some localities began to die in hundreds, 

 and on post mortem examination their livers were found to be filled 

 with a parasitic animal about three quarters of an inch long, somewhat 

 flat and leaf-like. It is known as the Liver Fluke or the " Liver-rot." 

 I shall briefly sketch its life history, which illustrates my point. One 

 fluke produces about half a million of eggs which are expelled from the 



