LETTERS TO BROTHER JOHN. '89 



laws, you must also admit the propriety of what I 

 shall hereafter say as to diet and regimen ; as the 

 correctness of the latter will depend solely upon the 

 correctness of the former. As, for instance, if you 

 admit now that sensibility can be worn out, and 

 that such and such a regimen is calculated to wear 

 it out, then, I say, you must also, of necessity, 

 admit that this particular regimen is injurious to 

 health. When I come to apply these laws to the 

 subjects of diet and regimen, I repeat, that either 

 what I shall say then must be true, or what I am 

 about to say now must be false. 



As all the actions of the body are performed by 

 contractions, and as these contractions are per- 

 formed in virtue of the contractile power, that is, 

 contractility, it is evident that the physical strength 

 of the body that strength by which we raise heavy 

 weights, walk, run, leap, &c will be in proportion 

 to the energy of the contractile power. A high 

 degree of contractile power, then, is synonymous 

 with strength; and a low degree of contractile power 

 is synonymous with weakness. 



But not only are the motions of the limbs per- 

 formed by contractions, but also those motions of 

 the internal organs by which nutrition is effected. 

 Now, this being the case, and as these internal con- 



