638 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



Two large demonstration pastures in southern Texas, one in Vic- 

 toria County and one in Calhoun Countj^ wore utilized for the pur- 

 pose of demonstrating the feasibility of reducing the tick infestation 

 to a practically negligible quantity. Cattle were removed from these 

 pastures in the spring and returned in the fall. It was found in 

 both pastures that the cattle were practically free from ticks in the 

 spring, although the cattle which had been pastured elsewhere were 

 heavily infested. In the demonstration pastures a continuous and 

 very profitable gain in weight was made and in the others the cattle 

 w^ere in such condition from tick infestation that very low prices 

 were secured. 



Efforts to cause the parasite of the brown dog tick to attack the 

 cattle tick were continued but w^ithout definite results, except as to 

 methods of manipulation that will assist in future work. Ship- 

 ments of the parasites were made to South Africa and Italy for 

 attempted introduction by the government entomologists. 



Progress was made in the work on the species of ticks which trans- 

 mit spotted fever of human beings. An agent traveled through some 

 of the Northwestern States to obtain material to reveal the distribu- 

 tion of the species. This work will result in an exact knowledge of 

 the geography of the disease, or at least the region in which it can 

 spread if once introduced. Following this preliminary work, a 

 camp laboratory w^as established in the Bitter Root Valley, in Mon- 

 tana, where a very virulent phase of the disease exists. Through this 

 laboratory a study was made of the distribution of the dangerous 

 ticks in the locality. There are many points that need investiga- 

 tion. For instance, the disease occurs commonly on the west side of 

 the valley but rarely on the east side. This phenomenon is probably 

 due to some limitation in the distribution of the ticks. In addition, 

 studies of the life history, habits, and means of control will be con- 

 ducted and demonstrations will be inaugurated if the investigational 

 work seems to warrant it. This work is in cooperation Avith the 

 Montana State University and the Montana board of health. Prof. 

 R. A. Cooley, of the university, has become a collaborator of the 

 Bureau, and is directing the work. On account of his extensive study 

 of the problem it is considered that the Bureau is fortunate in being 

 able to perfect this arrangement. One of Professor Cooley's stu- 

 dents is stationed at the camp. The Biological Survey of the De- 

 partment is also cooperating. It has stationed two men in the field 

 to determine the limitations in the range of the various animals 

 which act as hosts for the ticks. The Montana board of health has 

 agreed to place a physician at the camp. The work is therefore 

 organized in a comprehensive way and should yield important 

 results. 



In addition to the work in the Bitter Root Valley a large amount 

 of information concerning the distribution of the ticks throughout 

 the Rocky Mountains region was obtained by means of circulars. In 

 this wa}'*^ over 500 lots of ticks were obtained, representing prac- 

 tically as many localities. This will enable the Bureau to map the 

 distribution of the form which is now known to be pathogenic in 

 nature and of others wdiich may later be found to be capable of 

 transmitting diseases. 



In addition to the main lines of work indicated, progress has been 

 made in the study of some of the other important ticks. A number 



