BIPEDS AND QUADRUPEDS. 97 



of the jockey whip that will raise an ostensible wale 

 on the fine skin of the race-horse, would leave no 

 mark, or probably be little felt, on the thick hide of 

 the ass ; but this in no way proves the last-men- 

 tioned patient and ill-used animal is not as sensible 

 to suffering as the former, if that is done which 

 brings on suffering to either, or rather both. 



I conceive the sensibility to pain depends much 

 on the state of the nervous system ; and without at- 

 tempting or intending to trespass on pathological 

 causes or effects, I conclude the sensibility of that 

 nervous system is influenced a good deal by the state 

 of health and spirits ; in some proof of which, I be- 

 lieve it is fact, that invalids will often undergo a severe 

 operation with less complaint of pain than the per- 

 son in rude health ; so I conceive that a great deal 

 of the insensibility to whip or spur usually ex- 

 hibited by the ass, does not wholly arise from thick- 

 ness of skin, but that from the absence of any thing 

 like generous and stimulating diet from his birth, 

 and this, accompanied by severe drudgery and con- 

 stant brutal usage, brings the nervous system of the 



