232 LETTERS TO BROTHER JOHN. 



has lost in supplying the waste which the hocly lias 

 undergone during twenty-four hours of life. 



To make this more simple and clear, let us sup- 

 pose, for argument's sake, that the waste of the 

 body in twenty-four hours is just twenty-four 

 ounces. Now, when these lost twenty-four ounces 

 of the hody have been restored to it out of the 

 blood, then the blood will have lost twenty-four 

 ounces : and the object of eating being wholly 

 and exclusively to supply this deficiency thus pro- 

 duced in the blood, it is perfectly evident that the 

 quantity of food required in twenty-four hours is 

 precisely so much as shall be capable of conversion 

 into twenty-four ounces of blood; that being the 

 exact supposed quantity which the blood had lost in 

 supplying the waste of the body in twenty-four hours. 



I do not mean to say that twenty-four ounces do 

 indeed form the precise quantity of daily waste ; 

 but it seemed necessary to fix on some definite and 

 specified quantity, in order to illustrate more plainly 

 the principle of eating. There is, in fact, no fixed 

 quantity of waste ; for the quantity must always be 

 in proportion to the extent of bodily exertion : and, 

 for the same reason, the quantity of food daily ne- 

 cessary can neither be fixed, definite, nor specified. 



Now, if a man eat more food than is necessary to 



