NEMATODA, THREAD-WORMS 



547 



with the mosquitoes, and a part are destroyed. The female mosquitoes die 

 after depositing their eggs in water. But the mature filaria, meanwhile, have 

 acquired the power of living for a time in water. With the water they' enter 

 the human host and there, chiefly in the lymph-vessel system, they become 

 sexually mature animals. 



The male parasite is about 83 mm. in length, and has the thickness of a 

 hair of the head, while the female is 155 mm. in length and 0.7 mm. in 



Fig. 53. — Fii/Abia Embkyos. 

 This preparation I owe to the kindness of Professor Magathaes of Rio de Janeiro. 



breadth. The posterior end of the male is pointed, and rolled in a spiral. 

 The sexual opening of the female is close to the head. In fresh blood the 

 embryo shows active movements of both ends; it is perfectly transparent, and 

 only in the middle of a parasite may a few granule clumps be recognized. 

 Scheube found them upon the average 0.216 mm. long and 0.004 mm. broad. 

 The home of the filaria is tropical Asia, Africa, America, and Australia. 



Besides the filarise of Bancroft and Cobbold, other blood filarige are also 

 found. The filaria Magathaesi must first be mentioned. It is decidedly larger 

 than those previously named, and in Brazil lives in the heart of man. Fur- 

 thermore, Manson has described the filaria sanguinis hominis major — the 

 filaria diurna, Manson ; the filaria sanguinis minor — the filiaria perstans, Man- 

 son ; the filaria, Demarquayi ; the filaria, Ozzardi. The sexually ripe form has 

 not yet been found, and v. Linstow believes these filaria to be developmental 

 phases of one and the same embryonic larval form. 



The filaria produce marked symptoms in the lymphatic system, the walls 

 of which show inflammatory changes. Thrombosis and cicatricial closure of 

 the lymphatics cause varicose dilatation of the peripheral vessels and the forma- 

 tion of lymph-cysts. These rupture and their contents are set free in the 

 urinary bladder, under the cutis, or in other tissues. The perilymphatic con- 

 nective tissue is also inflamed. Finally symptoms are produced which resem- 

 ble elephantiasis. 



