bands round the body of the worm, are eminently suited 

 for aiding its progress through the tissues of the host, 

 the animal actually boring its way along. Such an 

 architecture, indicating, we believe, the necessity for 

 translation of the animal in the host's body, would be an 

 extravagant waste in the case of a Filaria which merely 

 had to extrude embryos into the circulating blood and to 

 whom practically all the fibrous tissues, internal and external 

 should be equally advantageous for its development. 



This second theory is beset with a grave difficulty, how- 

 ever, which consists in the dense fibrous capsule which 

 surrounds the worm, especially in the older nodules, and 

 which is evidently a reactive process on the part of the 

 tissues of the host to the irritative presence of the parent 

 worm or of its struggling embryos. It can hardly be 

 imagined that the adult form* can escape from such a prison 

 to wander to the surface and extrude its embryos. We 

 are not at all certain, however, that this imprisonment in 

 a thick capsule is the normal fate of the Filaria. We think 

 that it is quite possible that, on their way to the surface 

 and especially when the sexes are in conjugation, a certain 

 number, perhaps many, of the adult worms, as the result 

 of the irritation to the tissues that their progress through 

 them produces, are arrested and finally surrounded by a 

 librous capsule, which becomes thicker as time advances 

 but which still leaves the worm and its embryos alive in 

 the centre. 1 Those females, on the other hand, which 

 • scaped this fate, would reach the surface, pierce the 

 . pideiiiiis. and liberate their embryos without perhaps doing 

 any noticeable damage to the hide or attracting the atten- 



1 Hanson ("Tmpi.-iil Di^u—," :inl Iviit . l!t.»3. p. «52» r-tWs to tlu> 



