life history would then probably occur in some fresh-water 

 animal and the re-introduction of the parasite take place 

 through drinking water containing these. So far we have 

 not succeeded in finding the embryos alive after having 

 been in water for more than a few days. 



Escape of the embryos from the nodules through the 

 agency of ingestion by a carnivorous animal can practically 

 be excluded. Dingoes (Canis dingo) are the only animals 

 in Australia that could play this role, and they could only 

 do so by eating the nodules from a bovine that had died by 

 accident in the bush, a comparatively rare event. Further, 

 Dr. Gibson fed a young pup on minced worm-nests and 

 bread for 15 weeks. On killing the animal 24 hours after 

 eating its last meal of this nature, he found no nematode 

 embryos in the blood and no living embryos in the stomach 

 or intestines, though numbers of partly digested ones were 

 found in the stomach and duodenum. 



Barnard and Park's suggestion of direct transmission of 

 the parasite we consider highly improbable. If such be 

 the case, one would expect that animals harbouring a 

 worm-nest would later develop an enormous brood of young 

 nodules. One of our colleagues, Mr. G. P. Darnell-Smith, 

 has, however, inoculated a number of living embryos into 

 the subcutaneous tissues of a calf six months old and 

 into a rabbit. As the former was only inoculated a short 

 time ago, no results can yet be expected. The rabbit was 

 also inoculated, but no embryos could be seen in blood 

 smears taken lour months later. 



Fulleborn 1 and Rodenwaldt 2 in dealing with O. volvulus, 

 mention that the embryos (which are similar in appearance 

 to those of O. gibsoni) have not yet been found in the blood, 

 though Brumpt' found them in the peripheral parts of the 



' Fulleborn, I.e., p. 15. ■ Fulleborn and Rodenwaldt, I.e., p. 83. 



