140 MOSQI'ITOKS 



of the city. Some jiart of it must also l)o attributcil to 

 the excollt'ut (luaiaiitine service iiiulor the cliaigc of the 

 United States Marine Hospital Service, but also, without 

 doubt, much of the result must further be attributed to the 

 hospital and barrack methods, and treatment of moscpiito 

 breeding'-places carried on under the direction of the 

 medical corps of the army. 



Mos(|uitoes and Filariasis. 



The first evidence scientifically obtained that moscpii- 

 toes play a ])art in the spread of a diseas*' was in the case 

 of the parasitic worms of the i^cnus Fil.-iria. w Inch are re- 

 sponsilde in Oriental tropical rei^ions for the terrible 

 disease known as elephantiasis. The aelult worm lives in 

 the skin of different parts of the body, Iodised in the 

 lymphatic vessels. The two s(>xes are fonnd side by side, 

 and are capabh^ of livini;- there a lonii' tinu'. They ob- 

 struct at certain points the flow of the lymi»h. This ac- 

 cumulates and dilates the vessels and ilic lyiupli.ilic 

 spaces. This mechanical distention is accompanied by 

 an irritation of the vessels and of the surroundinir con- 

 ned ive tissue. Thus, eh^jihantiasis ])ecomes established, 

 which, as is ^'enei'ally known, manifests itself in very dif- 

 fei'ent deq'rees and occui)ies ditlt'erent ])arts of the body, 

 such as the arm, the le<?, or the scrotum. 



The female Filaria enclosed in the Iyni])hatic vessels 

 is viviparous. The (Mnbryos to which she <;ives birth 

 sjii'ead in tln^ 1\ nipli and then with it into the blood, and 

 it is in the blood that they are commoul}' observed. 



