120 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



Senecio. — Some work on senecio was done with special reference to 

 an unexplained disease of horses in the neighborhood of Colorado 

 Springs, Colo. The work is not complete, but the results so far ob- 

 tained seem to indicate that another cause must be sought for the 

 horse disease. 



Leucothoe davisii, or black laurel. — In the mountains of Colorado 

 heavy losses of sheep have been ascribed to black laurel. A consid- 

 erable number of feeding experiments were conducted with this plant 

 and confirmed the popular belief of its dangerous poisonous charac- 

 ter. Other laurels are also being examined. 



Hymenoxys or pingue. — Pingue has been considered responsible 

 for loss of sheep in southern Colorado and New Mexico for some 

 years. Considerable experimental work has already been done upon 

 this plant, and during the past year further experiments were con- 

 ducted. 



Oak. — In Utah there is a disease of cattle popularly known as " oak 

 poisoning " or "summer sickness." It is popularly ascribed to scrub 

 oak which grows in great abundance over certain portions of the 

 ranges. Over other regions in the West and the Southwest it is said 

 that there are heavy losses of cattle from oak poisoning. Somewhat 

 elaborate feeding experiments have been conducted and certain 

 definite results have been obtained, but the solution of the entire 

 problem has not yet been reached. 



Dugaldia hoopesii, or sneezeweed. — For a long time complaints 

 have been made of the loss of sheep on the Utah range by what is 

 popularly known as the " spewing sickness." It was at first assumed 

 from the symptoms that in all probability the loss was occasioned by 

 death camas, but it was deemed necessary to obtain definite proof. 

 In the summer of 1915 a somewhat elaborate series of feeding experi- 

 ments were conducted, which proved beyond doubt that the spewing 

 sickness is caused by the sneezeweed. The symptoms and pathology 

 of the disease have been worked out in considerable detail. A pre- 

 liminary report of this work has been prepared for publication. 



Eupatorium. — A study of the effect of eupatorium has been carried 

 on in preceding years because of the supposed connection of this plant 

 with milk sickness. This work was continued in Illinois during the 

 fall of 1915. A series of feeding experiments were conducted on a 

 farm where milk sickness was known to exist, and this work was sup- 

 plemented by laboratory work in Washington. While the cause of 

 the milk sickness is not yet definitely shown, the investigation has 

 yielded certain information as to the properties of the plant in ques- 

 tion. 



BRANCH PATHOLOGICAL LABORATORIES. 



The branch pathological laboratory at Chicago, besides carrying 

 on routine work in aid of the meat inspection, has studied a condition 

 affecting the bones of cattle, in which the marrow of the irregular 

 bones, especially the vertebrae, ribs, and sternum, become dark red 

 in color and soft, in some cases slightly gelatinous, resuming an 

 embryonal character. While the lesions are suggestive of some form 

 of infection, experimental animals (rabbits and guinea pigs) have 

 been inoculated subcutaneously and intraperitoneally with varying 

 amounts of a saline suspension of the marrow, with negative results. 



