396 tJNIVEHSITY OF VIRGINIA PUBLICATIONS 



The following signs and symptoms were observed: 



1. Emaciation, in the majority of the animals selected. The other locoes 

 from the same flock were undernourished, often stunted, not always ema- 

 ciated. 



2. Loose irregular incisor teeth, in nine out of eighteen cases. No note 

 was made in the other cases of the condition of the teeth. 



3. Weakness, and stiffness of gait in nearly all the very ill animals but by 

 no means in all animals pointed out by the ranchers as typical locoes. 



4. Dullness and apathy in the ill animals, but not in those less severely 

 diseased. The iller animals were apt to wander off from the flock. 



5. Tremor and nystagmus in one case (No. 1). 



6. Coryza and bronchitis, in some flocks, not in all. 



7. Rough, irregular fleece, occasionally. 



Of these signs, the condition of the teeth is difficult to explain. The 

 fairly constant findings, such as emaciation and under-development, weak- 

 ness and stiffness, dullness and apathy are common to so many forms of 

 disease, that they have no value for the differential diagnosis of locoism. 

 The coryza, bronchitis, etc., were sufficiently explained by the autopsy 

 findings. 



The clearest and most detailed clinical picture which the eighteen sheep 

 allow us to draw is about this : The animals suffer from prolonged and pro- 

 gressive malnutrition; in the case of lambs, the animal is undersized; adult 

 animals become thin or emaciated. As malnutrition becomes severe, the 

 animal loses strength and energy, becomes listless, and does not keep up 

 with the flock. As its strength diminishes the animal begins to walk in an 

 awkward manner, the hind legs especially moving stiffly, as if they were 

 parts of a mechanical toy. With these symptoms at least one-half the cases 

 show loose and irregular incisor teeth. Now it is plain that, aside from the 

 condition of the teeth, the above symptoms may result from any one of 

 many causes which bring about malnutrition. 



This forces us to the conclusion that typical and diagnostic symptoms 

 of "Jjocoism" either do not exist or are so elusive that they escaped both 

 my painstaking examinations and also the observations of the experienced 

 ranchmen who gave their assistance. Inasmuch as the ranchmen were certain 

 that the animals selected for study were severe cases of typical loco disease, 

 there seems to be no escape from the above conclusion. It seems then 

 that it wiU be either impossible, or exceedingly difficult, to construct the 

 symptomatology of loco disease from animals studied on the ranches. 

 Fondness for the locoweed. is commonly regarded as the most constant and 

 characteristic symptom exbibited by locoed animals, but even this was 



