26 PRESIDENTIAL ADDRESS. 
WorM-NeEsts In CATTLE. 
In 1911 I read before this Society* a summary of the 
information available regarding Onchocerciasis in cattle. 
Since then, a few important papers have been published 
relating to this condition in Australian oxen. 
Mr. C. J. Poundt (1911) failed to find larvae im the 
circulating blood by day or by night, and his attempts at 
direct infection were unsuccessful. He found the adult 
parasite in a sheep. 
In 1912, my former colleague, Dr. J. B. Cleland{ 
discovered the pre-ence of the parasite in nodules in calves 
which had been born and reared on Milson Island in the 
Hawkesbury River, N.S.W., not far from Sydney, this 
showing that ‘it is therefore practically certain that 
infection occurred on the island itself and, further, it is 
obvious that the source of infection must have been some 
of the older cows or other cattle with which the island 
was originally stocked ’’ §. He discovered the possibilities 
of various insects acting as transmitting agents and 
inclined strongly to the view that, whilst mosquitoes, 
tabanids, sand flies, etc., could not be absolutely excluded, 
yet it was quite likely that true cattle-lice (Haematopinus 
spp.) or Stomoxys calcitrans, particularly the latter, is 
the vector. He also reviewed the various possible modes 
of transmission of the filarial embryos (p. 140). 
S. G. Thorn in 1912|| mentioned that he had failed 
to infect various freshwater organisms with Onchocerca 
larvae. 
*T, H. Johnston. “‘ On the Occurrence of Worm Nodules in Cattle 
—a summary.” P.R.S., Queensland, 23, 1911, pp. 207-231. 
+ C. J. Pound in Ann. Rep. Dep. Agr. 1910-11 (1911), p. 67. 
tJ. B. Cleland. ‘Some Notes and Suggestions in connection with 
the Etiology of Bovine Onchocerciasis.’”” Austr. Med. Gazette, 1912, 
p. 4; and “ Observations on the Mode of Dissemination of Onchocerca 
gibsoni.”” in second report Govt. Bureau of Microbiology, Sydney, 
1912, pp. 138-141, prefaced by ‘“‘ Remarks on the problem of the dissemi- 
nation of Onchocerca,” by Dr. F. Tidswell, l.c., pp. 137-8. 
§ Dr. Tidswell (/.c., p. 137) has shown that the original stock had not 
been exposed to infection from other sources for a period of five years, 
1906-1911. 
|| Rep. Govt. Bacteriologist—Dept. Agr. Stock. Ann. Rep., 1911- 
12 (1912), p. 88. 
