380 UNIVEKSITY OF VIRGINIA PUBLICATIONS 



changes described by Marsh (1. c.) and reviewed below in Section E. An 

 increase in the fluid beneath the meninges and in the ventricles of the brain 

 has been described by Stalker and by Schwartzkopf. Scheuchardt states 

 that Schwartzkopf found no bacteria in his cases. 



Prognosis. The outlook for locoed animals is usually bad. If the 

 disease is detected in the early stage the animal may be saved if it is fed 

 up on grain, hay, etc., or if sent to a country free from the weed. As a rule 

 the disease is not detected early, and the general attitude of the ranchman 

 is that of non-interference. Even after an apparent cure the animal will 

 relapse if turned out to graze in the former pasturage. 



B. EXAMINATIONS OP "lOCOED" SHEEP. 



Several hundred "locoed" sheep were seen on various ranches in Mon- 

 tana. No locoed horses could be found. Loco disease of cattle is a rarity 

 in Montana and no cases could be found. Experienced sheep raisers selected 

 a few of the illest and most typically locoed sheep from among the invalids 

 and turned them over to me. Animals selected in this way furnished the 

 materials for the following study. 



Six of the illest lambs obtainable were fed for about two weeks on loco- 

 weed {A. spicatus), gathered fresh every day. The animals did not like the 

 food, and at first ate sparingly of it, but more abundantly after a few days. 

 No change in their condition could be detected as the result of this diet, and 

 no acute symptoms were induced (see cases 8, 9 and 11). 



A synopsis of the cases examined follows. The anatomical diagnosis 

 was usually confirmed by the microscopic study of tissues fixed in Zenker's 

 fluid or alcohol, sectioned and stained with hematoxylin and eosin. The 

 central nervous system was not studied microscopically, but the brain, 

 •cord and membranes were examined at autopsy. 



Histories of sheep studied during September and October of 1903. 



Animal No. 1. Sheep, female, about eighteen months old from the Briggs-Ellis 

 Ranch, Big Timber, Montana (Mr. James Vestal), September 24. This sheep was 

 picked out by Mr. Vestal from an invalid band of between fifteen and thirty "locoed" 

 animals, and selected by him as presenting the features of loco most typically and 

 most severely. 



When examined, animal was in corral, separated from other sheep; appeared 

 apathetic, not eating nor noticing its surroundings. When alarmed, it ran off at a 

 trot with a stiff gait and stumbling, the legs flying out in an incoordinate manner. 

 The sheep was very weak and tremulous, especially in the hind legs, the tremor worse 

 on movement. There was slight lateral nystagmus. When laid on the ground the 

 animal was hardly able to rise. The hind legs were not able properly to support the 



