Suggested means of transmission of the disease.— By 

 analogy with Filaria bancrofti, Oobbold (F. nocturna, 

 Manson) of man, an intermediate host might be expected 

 to be the agent of transmission from animal to animal. 

 Such a host would most likely be a species of mosquito, 

 perhaps a biting fly, or possibly a tick, all being animals 

 which pierce the skin and suck blood. Since the tumours 

 are, in most instances, well below the surface of the skin 

 and their capsules are thick, it would further be necessary 

 for the embryos, set free from the mother, to escape into 

 and be present in the general circulation. As the embryos 

 would be extruded from the vagina of the parent into the 

 serous or sero-sanguinolent fluid present in the innermost 

 sac, they would require to pass out from this by way of the 

 lymphatics, or through the small vessels after piercing them. 

 Gibson describes finding the embryos both in the capsule 

 of the worm-nests and in the trabecular network, the 

 majority being in lymphatic spaces, but occasionally some 

 were found in the interior of blood-vessels. Though, as 

 this author has pointed out, the fibrous capsule and tra- 

 becule are well supplied with blood-vessels, we have not 

 noticed any large and definite vascular trunks escaping 

 from the nodules. This abundant blood-supply is therefore 

 probably obtained by smalt vessels piercing the capsule at 

 many different points, and by these and by the lymphatic 

 connections, the embryos could enter the systemic circu- 

 lation. Gibson failed to find the embryos in the general 

 blood stream, but adds that his observations were very 

 imperfect. Barnard and Park refer, in an addendum to 

 their paper, to finding "young Spiroptera in some of the 

 blood-vessels " but do not state whether in those of the 

 general circulation or of the wall of the worm-nodule. 



We ourselves, in sections of the growths, have seen the 

 embryos free in the fibrous stroma surrounding the coils of 



