188 EXPEBIMENT STATION BECOED. 



The investigations showed X. fllicoUis, in spite of but few records of its oc- 

 currence, to be extremely abundant at all seasons, and it was found in a large 

 percentage of lambs and yearlings suffering from gastrointestinal troubles, as 

 well as in a number of apparently healthy animals. The nematode usually occurs 

 in the duodenum, but in case of heavy infestation is also found in other parts 

 of the small intestine and has been recorded from the fourth stomach as well. 

 While in a majority of cases it occurs in relatively small numbers, the author 

 has occasionally observed thousands in the duodenum alone, the lambs thus 

 heavily infected always exhibiting .symptoms of helminthiasis. To what ex- 

 tent the symptoms are due to the presence of \. filicoUis could not be de- 

 termined, as this nematode is always associated with other parasites both in the 

 .small intestine and other parts of the alimentary tract. Among the parasites 

 found associated with it in the small intestine were the taiieworm iloniezia 

 expansa, and the nematodes Bunostomum trigonocephahim, Ostertapia circuni- 

 cincta, Cooperia oncophora, Trichostroiigylus vitrinus, and Strongyloides papil- 

 losus. 



" The eggs of A^ filicoUis when laid contain an embryo with seven or eight 

 cells ; they pass out of the infested host with the feces. Even under favorable 

 conditions development takes place slowly, and the embryos are not ready to 

 hatch until 24 to 28 days have elapsed. In their early stages the embryos are 

 not able to withstand desiccation and are killed if frozen or subjected to high 

 temperatures. ... 



" The sheathed larvae are often retained for a long time within the egg- 

 shells, and both in this position and after hatching can resist complete desicca- 

 tion for considerable periods (20 months or even longer) ; when dried they are 

 able to withstand freezing as well as temperatures much above those likely to 

 be met with in the open. The free larvc-e will live for a considerable time in 

 water. They possess well-<leveloped migratory instincts and climb vertical sur- 

 faces such as grass .stems and blades and tlie glass walls of the vessels in which 

 they are kept. The sheaths are cast off by the larvje when these are subjected to 

 temperatures approximating to the blood temi>erature of the host ; completion 

 of the .second molt occasionally also takes place at laboratory temperatures under 

 certain abnormal conditions. 



" No infection experiments were made on sheep, but other evidence shows 

 that these animals must become infected by swallowing the sheathed larvje 

 either when free or while still inclose<l in the eggshells. A number of young 

 stages of the parasite were met with in the intestines of sheep, the smallest of 

 these being only little more advanced in structure than the larv£E just after 

 ecdysis." 



A list of 24 references to the subject is appended. 



T7mbilical necrobacillosis in lambs, W. B. Mack {Amer. Yet. Rev., 47 

 {1915), A'o. 5, pp. 592-597, figs. 3). — The author reports upon an outbreak of 

 this disease in Nevada in which 70 per cent of a loss of 2,200 lambs was due 

 to this affection, as previously noteil (E. S. R.. 33. p. 676). 



The State, the owner, and the veterinarian in relation to hog cholera serum 

 and virus, M. H. Reynolds {Amer. Vet. Rev., ^7 (1915), No. 5, pp. 558-^69).— 

 The author describes a plan for hog cholera control work by and under the 

 supervision of the State and reports practical field tests of it made in Min- 

 nesota. 



Hog cholera, E. A. Cahili. {-Jour. Amer. Vet. iled. Assoc., 48 (1915), No. 1, 

 pp. 31-38). — A discussion of this disease, particularly as regards Massachusetts 

 conditions. 



Directions for the dissection and study of the cranial nerves and blood 

 vessels of the horse, G. S. Hopkins ([Ithaca, N. Y.]: Author, 1913, pp. 35, 



