VETERINARY MEDICINE. 377 



The investigations conducted prove that the larva of 0. gihsoni may penetrate 

 the thick cai^siile which surrounds the nodule and also the skin of the animal 

 in small numbers. Sometimes larvte taken out of a fresh nodule still showed 

 slight movements after having been kept for 28 to 30 hours in water at a tem- 

 perature of from 15 to 18° O. (59 to 66.4° F.) At room temperature all move- 

 ments of the parasites had ceased after about 10 to 12 hours. 



About GO stable flies were experimented with on different occasions and the 

 intestinal content examined after short varying intervals of one to two days, 

 but in no instance could anything be found even resembling a larva. Similar 

 experiments were carried out using mosquitoes for feeding experiments, as 

 Culcj; fatigans, Culicclsa vigilax, and Mansonia uniformis, with entirely nega- 

 tive results. Although it was repeatedly observed that the Onchocerca larvte 

 from fresh nodules are taken up by crustaceans belonging to the genus Cyclops, 

 further development of the larvse was never observed. 



Further investigations into the etiology of worm nests in cattle due to 

 Onchocerca gibsoni, J. B. Cleland (Jlclbounie, AKstralia: Govt. [IdlJfl, pp. 

 56, pis. 5; (lis. in Pub. Health [London], 28 (1915), No. 4, pp. 90-95).— This is 

 a report of investigations conducted in continuation of those previously noted 

 (E. S. R., 27, p. 785). Although the author has previously expressed the 

 opinion that the balance of evidence thus far available favors the stable fly 

 (Stomoxys calcitrans) , a hematophagous species, as being the insect vector con- 

 cerned in the transmission of this parasite, the Investigations have been ex- 

 tended to test other possible channels. 



The more imporant results obtained are the determination that various 

 Muscidae, as well as mosquitoes, can ingest the embryos of O. gibsoni when given 

 access to a freshly opened nodule ; that in the case of S. calcitrans not only can 

 the embryos be ingested but they may remain alive and active in considerable 

 numbers within the alimentary canal for a period of three days at least; and 

 that in case of Musca domestica and M. vetttstissima, both common flies, the 

 embryos can be ingested, although in the few experiments conducted they have 

 not been found alive in the alimentai-y canal of these flies even 24 hours after 

 feeding. The possibility of animals acquiring partial immunity to worm nest 

 infestation and the possibility of breeds immune to the formation of worm nests 

 is i-eferred to. 



On the migration of the larvae of Onchocerca gibsoni through the capsule 

 of the worm nodule, W. Nicoll (Ann. Trop. Med. and Par., 8 (191^), No. 3, pp. 

 609-621). — ^The experiments here reportetl show that Onchocerca larvse can 

 and do make their escape through the capsule of the worm nodule. They 

 usually do so in small numbers, but may at times, or in some cases, migrate in 

 comparatively large numbers. 

 A bibliography of 8 titles is included. 



Animal parasites, with special reference to the sheep tick (Melophagus 

 ovinus) and the biting sheep louse (Trichodectes sphaerocephalus), W. W. 

 Feoggatt (Agr. Gaz. N. S. Wales, 25 (191-i), No. 9, pp. 765-770, pi. 1, figs. 6).— 

 A discussion of eight ectoparasites and their occurrence in Australia. 



Concerning certain cytological characteristics of the erythroblasts in the 

 pig embryo, and the origin of nonnucleated erythrocytes by a process of 

 cytoplasmic constriction, V. E. Emmel (Amer. Jour. Atuit., 16 (191^), No. 2, 

 pp. 127-205, figs. //.5). — "In conclusion, therefore, it may be stated that the 

 data derived from the present investigation involving the study of blood cul- 

 tures, living and fixed blood vessels in the pig embryo, together with the ob- 

 servations of other investigations for both red and white blood cells in various 

 mammals, raises the question whether the origin of nonnucleated erythrocytes 



