272 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



THE ZOOLOGICAL DIVISION. 



The Zoological Division, of which Dr. B. H. Ransom is the chief, 

 has continued the investigation of animal diseases of parasitic origin 

 and the study, collection, and determination of animal parasites. 



ROUNDWORMS IN SHEEP. 



The investigations relative to stomach worms and other round- 

 worms jDarasitic in sheep have been continued. No new facts of im- 

 portance bearing on the life history of these parasites, their preven- 

 tion or treatment, have been discovered. 



A zoological study of all the roundworms parasitic in the ali- 

 mentary tract of ruminants has been completed and prepared for 

 publication. Including newly discovered species, the different kinds 

 of roundworms occurring parasitic in the alimentary tract of rumi- 

 nants are about 50 in number, and 33 of these have been found in the 

 United States. 



GID IN SHEEP. 



The first jDart of a comprehensive study of the gid disease of sheep 

 and the parasite which causes it has been completed and the manu- 

 script sent to the printer. Except for rare cases the disease as yet 

 appears to be limited to the State of Montana, and it is enzootic only 

 in the northern half of that State. 



A common opinion that dogs do not eat the brains of sheep because 

 of inability to break through the skull, and hence that the infection 

 of dogs could not come from eating the brains of infested sheep, was 

 proved by experiment to be incorrect. It was found that dogs of the 

 size of an ordinary sheep dog readily extract the brain from sheep 

 skulls, and also that they may in some cases devour nearly the entire 

 bony part of the skull. A report of these experiments is given in 

 Bureau Circular 159. 



SHEEP SCAB. 



A compilation of reports made by Bureau inspectors as to the 

 results of dipping sheep under federal supervision during the calen- 

 dar year 1909 indicates that lime-and-sulphur and tobacco-and-sul- 

 phur dips were much more efficacious than coal-tar creosote and 

 cresol dips. These results are similar to those obtained from a com- 

 pilation of the reports by sheep owners of dippings done during the 

 calendar year 1908. In both instances, however, the number of dip- 

 pings in coal-tar creosote and cresol dips of which reports were re- 

 ceived was rather small, so that it would perhaps be unfair to con- 

 clude that these classes of dips are generally less efficacious than 

 lime-and-sulphur and tobacco-and-sulphur dips. Nevertheless the 

 reports suggest that the opinion that the former classes of dips are 

 less reliable than the latter as remedies for sheep scab is not without 

 foundation. 



In cooperation with the Kentucky Agricultural Experiment Sta- 

 tion a series of experiments in the treatment of sheep scab with to- 

 bacco dips was carried out, in order to obtain information as to the 

 effect of the omission of sulphur upon the efficacy of these dips. 



