^«>. 205 



instances of the complaint which occur among such Horses ;\5 are fed 

 equally high, yet are kept out chiefly or altog-ether in the open air. 

 1 am well aware that costiveness is commonly considered to be a very 

 frequent cause of these disorders of the eyes, and the advantage 

 arising from turning out Horses to grass under those circumstances, 

 has been usually attributed to the cooling, opening effect of th.e 

 grass upon the bowels. 



Now, though I am far from being prepared to maintain that cos- 

 tiveness may not occasionally be concerned in the aggravation of 

 these complaints, yet, there is no fact of which I am more perfectly 

 satisfied than that the hot and foul air of stables is the prime and capi- 

 tal cause of them all ; with the exception only of those that are here- 

 ditary, and such as are occasioned by external injuries. 



But this opinion on account of its having considerable novelty, 

 may, perhaps, startle many, and produce some scepticism. It will 

 not however, I presume, be difficult to convince every one that the 

 hot and foul air of stables is at least capable of aggravating diseases 

 of the eyes. For, if Volatile Alkali whicl) has been proved to exist 

 so largely in the air of stables be capable of painfully stimulating a 

 sound and healthy eye, surely its effects upon one that is inflamed 

 and consequently extremely irritable, must be both highly painful 

 and prejudicial to the organ. In the human species we often find 

 when the eyes are violently inflamed that the natural stimulus of light 

 alone, becomes insufferably painful lo the patient. 



But, were we under those ciivumstances to sprinkle his apartment 

 frequently with hartshorn, we should certainly add to his suffeiings^ 

 ai>d materially aggravate the dfeease. 



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