512 SPOKADIC DISEASES. 



by White of Exeter, in White's Farriery, that the disease 

 occurred in one farm in Soutli Wales, from hay made the previous 

 year (1800), and concludes that "it seems more than probable 

 the hay had been over-ripe when made, and that the process of 

 "withering had not destroyed the irritating or noxious, or perhaps 

 narcotic, quality of the over-ripe grasses." — ( Veterinary Pajicrs 

 by Professor Dick.) 



I quite agree with Professor Dick that the disease is due to 

 some peculiar narcotic principle, that is developed in the grass at 

 this time, or which may be developed by the process of heating 

 and fermentation, when cut at an earlier stage of its growth; 

 for every-day experience proves to us that food, even rye-grass 

 included, has no effect in producing symptoms of cerebral dis- 

 turbance, when used in its ordinary condition, and that it is only 

 when in a transition stage, as it were, between grass and hay, 

 that it seems to possess toxic qualities. 



After careful observation I have arrived at the conclusion that 

 the seat of this disease is in the brain, the spinal cord, and their 

 meninges ; that, owing to the quality of the food, a degree of nar- 

 cotism is first produced, speedily succeeded by congestion and 

 other changes to be described in the morbid anatomy, and that 

 owing to this derangement of the great nervous centres, paralysis 

 of the digestive apparatus is the result, and the stomach becomes 

 sometimes engorged, from the fact that the animal continues 

 to feed, when the digestive as well as other functions are in 

 abeyance. 



This disease seems to have first attracted notice in 1787, the 

 summer of which was hot and dry. It raged in the south-west 

 of England and Wales in 1800 and 1819, the summers of which 

 were also hot and dry, prevailing most commonly amongst 

 horses at grass in low, wet pastures, where the grass was rank. 

 It was supposed to arise from their eating ragwort or stagger- 

 wort — Scnecio Jacolma — a plant supposed to contain a poisonous 

 principle, or some other poisonous herb ; but of this there is no 

 aljsolute proof We have, however, sufficient evidence to prove 

 that it originates when animals eat rye-grass in tlie condition 

 described. Mr. Gamgee says the disease may arise from gastric 

 derangement, brought about by eating wlieat, or even oats and 

 bran, in large quantities. My experience convinces me that this 

 js not the casCj .and that mere over-loading is more apt to pro- 



