426 UNIVERSITY OF VIRGINIA PUBLICATIONS 



maxillary space also appeared early. Marsh found (p. 92) that "during 

 the early period of loco feeding there were no symptoms of poisoning. 

 Horses and cattle will eat quite freely of the weed for a considerable period 

 with no apparent ill effects and may even gain considerably in flesh." 

 Marsh frequently speaks of malnutrition among his animals, and of their 

 starving to death, but it is only very recently (Farmers Bulletin 536, is- 

 sued May 1, 1913), that he has begun to come around to the view expressed 

 in my reports of 1903 and 1905 that underfeeding is one of the main 

 causes of the loss of Western live stock. 



Great individual differences were found to exist among animals in re- 

 gard to susceptibility to the loco poison; in general, the better bred animals 

 succumbed more quickly. Horses were the principal animals attacked in 

 regions where the Astragalus mollissimus prevailed. This was found much 

 more toxic than the Aragalus lamberti which did more damage to cattle 

 and sheep than to horses. 



In most of his experimental animals the symptoms were of sudden onset. 

 The weed was eaten by the animal with no evidence of injury until a rela- 

 tively short time before death, when symptoms developed rapidly. The in- 

 terval from the time the animal began to eat locoweed until its death 

 varied from two months and eight days to six months and nine days; with 

 cattle the average interval was about five months, with horses rather less. 

 If the animal ate only moderate amounts of loco, a fatal outcome was in- 

 defijiitely delayed. Cases of "acute" locoism in lambs were met with in 

 which death resulted in two or three weeks from the first eating of the loco- 

 weed. Age was not a factor in the disease, old as well as young animals 

 becoming locoed. 



Marsh states (p. 114), that there were certain quite definite anatomical 

 changes found at autopsy. 



The animals were strongly anemic. This anemia was indicated not only by 

 paleness of flesh and actual loss of blood, but by serous deposits in various parts of 

 the body. The blood was found to be poor in hemoglobin and commonly rather rich 

 in leukocytes. 



Elsewhere (p. 95) he says that the anemia 



is indicated not only by the emaciation and paleness of the flesh, but by the 

 excess of serous fluids of the body and by the deposits of organized serum in various 

 parts of the body. This is more especially marked at the base of the ventricle of the 

 heart. 



Elsewhere (Farmer's Bull. 380, p. 12) Marsh states: 



