HYPOTHESES 95 



phenomena. This hypothesis is based upon actual obser- 

 vations. The adult Filaria bancrofti passes living embryos 

 completely stretched out but still enclosed in the egg- 

 capsule which forms the loose sheath. The outlet to 

 the vagina of the female is a narrow muscular tube which 

 is just large enough to allow the exit of these embryos 

 one by one. These embryos, 7-5 //, in diameter, are 

 passed into the lymph in which the adult worm lies. 

 The lymphatic vessels anastomose freely, and frequently 

 the larger ones inosculate. 



Before reaching the main lymphatic trunk the lympha- 

 tics at least once subdivide into minute capillary lymph 

 channels in the;lymphatic glands. The lymph from the 

 skin passes first through fair-sized lymphatics and then 

 through these capillary tubes, which are of just sufficient 

 size to allow of the passage of filarial embryos, and con- 

 sequently no obstruction takes place in these lymphatic 

 glands. 



Occasionally, however, instead of stretched-out embryos, 

 ova with the embryos coiled up in them are passed. 

 These eggs have been seen by several observers in the 

 dilated lymphatics in which the parent worms lie. Such 

 eggs can only be passed if the adult aborts. This abor- 

 tion may be from defect or injury to the adult worm. 

 These eggs are up to 20 //, in diameter and are too large 

 to pass through the smaller lymph-channels or through 

 the lymphatic glands. 



An adult filaria situated in the lymphatics or on the 

 peripheral side of such glands would, if it aborted, pass 

 these eggs, and they would be carried with the lymph- 

 stream into the glands and block the lymphatic channels 

 in these and in the finer lymphatics. If eggs were still 

 passed they would now be carried by anastomosing vessels 

 and block up the finer vessels, and the glands in this 

 collateral circulation also. Provided the eggs continued to 

 be passed, in turn all collateral circulation of lymph would 

 be blocked, and there would be complete lymph stasis 

 in the skin and subcutaneous tissues which were drained 



