218 ON THE OCCURRENCE OF *' WORM-NODULES IN CATTLE 



agent being, by analogy, probably a blood-sucking insect.. 



We have suggested (C. and J., 1910, c, p. 98) that 

 imprisonment within a nodule may not be the normal 

 fate of 0. gihsoni. Leiper (1911, a, p. 13) thinks that an 

 examination of the viscera might reveal the presence 

 of the parasite in an unencapsuled condition, where it would 

 liberate its embryos into the blood stream. On the other 

 hand, one would expect that if encapsulation be abnormal, 

 that there should be a greater number of free than encap- 

 suled parasites, and the detection of the embryos in the 

 circulation should not be difficult. As all the known species 

 of the Onchocerca are found more or less embedded in 

 fibrous capsules, and as both males and females may occur 

 together in these nodules, and in such relation to each other 

 that fertilisation is readily effected, (Brumpt, re 0. 

 volvulus, quoted in Fiilleborn, 1908, p. 15, and in Fiilleborn 

 and Rodenwaldt, p. 83 ; Gilruth and Sweet, p. 10, re 0. 

 gihsoni), it seems to me that the connective tissues, especi- 

 ally the subcutaceous, are a normaJ, and probably the normal 

 habitat of the members of the genus. 



Origin of the parasite : — The original home of the 

 nematode is almost certainly the East Indies. We (C. and 

 J., 1910, c, p. 99) showed that it was probably by way of 

 Timor that infected animals (buffaloes) arrived in Xorthern 

 Australia. De Does had already recorded the occurrence of 

 worm-nests in cattle in Java, but we were at the time unaware 

 of his work. Gilruth and Sweet (1911, p. 34, addendum) 

 mention that cattle were imported from Coepang, about 

 1824, and from other parts of the East Indies in 1840. 

 This evidence supports the conjecture that infected animals 

 — either cattle or buffaloes, or both — came from the East 

 Indies to the Northern Territory, and became the means 

 of spreading the condition, which has gradually extended 

 its range southward, eastward and westward. 



It might be observed that 0. armillata (Railbet and 

 Henry, 1910, p. 250) parasitises Indian and Sumatran 

 cattle and buffaloes, and an allied or perhaps identical 

 worm occurs in Malayan and Indian cattle and buffaloes 

 (Daniels, Tuck, Leiper, Lingard). 0. armillata infests the 

 aortic walls. 0. gutturosa (Neumann ,1910, p. 270) occurs 

 in the cervical ligament of cattle in Northern Algeria and 

 Tunis. These parasites are distinct from 0. gihsoni. 



