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In summing up Marsh's work, it seems that he has called attention 

 to a disease which develops in some of the animals which eat locoweed. Not 

 all loco eaters get it, but chiefly those which eat locoweed almost exclusively. 

 There are great individual differences in susceptibility among animals to 

 the poisoning. Pecuhar nervous and mental symptoms with progressive 

 weakness, paresis, or partial paralysis of the hind quarters mark the prog- 

 ress of the disease, together with an increasing tendency to eat locoweed. 

 The disease develops suddenly two or three months after beginning to 

 eat the weed. The animals die of starvation, and at autopsy show serous 

 effusions; a peculiar exudate in the vertebral canal, either outside the dura 

 or around the spinal cord, with congestion of the vessels of the brain and 

 occasionally hemorrhages into the lateral ventricles. There is congestion, 

 or ulceration, or both, in the stomach of horses, and in the fourth stomach 

 of cattle or sheep. The anatomical condition may vary more or less in 

 regard to the central nervous system and the stomach. 



Several diseases have been described which somewhat resemble Marsh's 

 "loco disease." Pica, or licking disease (Nagesucht; Lecksucht), is inter- 

 esting, as it also bears a relation to the soil conditions, and to certain hays 

 in the diet. This disease, which, according to Hutyra and Marek {Spezielle 

 Pathologic und Therapie der Haustiere, 3rd edition, vol. 1, p. 960), affects 

 cattle almost exclusively, when confined to stables for long periods, is 

 produced by certain kinds of hay, depending upon whether the hay was cut 

 before or after the bloom, etc. Hay from certain localities only will produce 

 the disease, and there is apparently an obscure relationship between the 

 disease and the poverty in soda and lime salts, or excess of potash salts 

 in the hay. The symptoms of the disease are like locoism, and the gastric 

 mucosa is inflamed but there is no description of any spinal exudate. 



Catarrh of the fourth stomach, chiefly in cattle, would readily pass for 

 loco disease except that no special changes have been described in the cen- 

 tral nervous system. It is interesting to note that this disease may follow 

 various kinds of improper food, and that highly nitrogenous foods hke 

 vetches may produce it. 



Of more interest are the descriptions of meningo-encephalitis, for here 

 the description both of symptoms and of anatomical changes agree rather 

 better with Marsh's account of loco disease. Law {Veterinary Medicine, 

 vol. Ill, 3rd ed. p. 95-6) makes the following statement: 



Among the most common causes of encephalitis in horses is an injudicious dietary. 

 Overfeeding with grain, but especially with grain and seeds that are rich in albumi- 

 noids, deserves the first mention. The various leguminous seeds, peas, beans, tares, 

 vetches, and the ripened leguminous fodders, clover, alfalfa and sainfoin, are espe- 



