BUREAU OF ANIMAL INDUSTRY. 129 



cacious against lice. A period of 20 days is probably amply suffi- 

 cient to free premises of cattle lice if cattle are excluded. The experi- 

 ments are incomplete with reference to the short-nosed cattle louse, 

 so that the conclusions stated above do not necessarily apply to this 

 species, which may prove to be more difficult to eradicate. Certain 

 observations were made indicating that it is more resistant than the 

 other two species. 



Ox warbles. — Experiments in the treatment of -cattle to eradicate 

 warbles are in progress in Utah, Colorado, and New Mexico, but 

 results will not be reached until next year. 



Miscellaneous. — Experiments in treatment for lice of sheep, goats, 

 and hogs and for sarcoptic mange of cattle and hogs are in progress 

 in Colorado, Utah, California, and elsewhere, but no definite results 

 have yet been obtained. 



In cooperation with the Insecticide and Fungicide Board, tests of 

 various proprietary remedies for the destruction of external parasites 

 of live stock have been carried out or are still in progress. 



ANTHELMINTICS AND TREATMENT FOR INTERNAL PARASITES. 



Experiments recently carried out indicate that anthelmintics are 

 commonly less effective than they are generally supposed to be. Cer- 

 tain remedies most used by physicians and veterinarians for the re- 

 moval of parasitic worms, when administered in the customary doses, 

 have been found to be less effective than other substances not in com- 

 mon use as anthelmintics. Some of the latter have given very favor- 

 able results imder experimental conditions, and promise to prove 

 more satisfactory for practical use than those now employed. 



Various proprietary articles sold as insecticides or fungicides and 

 for which anthelmintic properties are also claimed by the manu- 

 facturers have been tested in response to requests from the Insecticide 

 and Fungicide Board. 



INVESTIGATIONS OF PARASITIC PROTOZOA. 



In continuing studies of the life history of Sarcosporidia further 

 facts have been determined which throw a new light upon the ques- 

 tion of the systematic relationships of these parasites. Of greater 

 practical interest is the confirmation of Negri's work, generally over- 

 looked or disregarded, by which it has been shown that sarcosporidio- 

 sis may be transmitted to healthy animals by feeding them the feces 

 of affected animals in certain stages of the disease. The feces are 

 still infectious after drying. It seems quite probable that the inges- 

 tion of feces from diseased animals, or of food or water contaminated 

 with infectious fecal material, is the usual mode of infection with 

 sarcosporidiosis in the case of herbivorous animals, which obviously 

 do not acquire their infection in the way the disease is commonly 

 transmitted in the laboratory, namely, by the feeding of muscle con- 

 taining the parasites. 



Investigations have been begun of the disease of turkeys known as 

 blackhead or infectious entero-hepatitis, as to the causative agent of 

 which several opinions have been expressed. So far as the investiga- 

 tions have gone it appears quite certain that the disease is not a coc- 

 cidiosis, but positive conclusions as to the nature of the causal organ- 

 ism have not yet been reached. 



