264 LETTERS TO BROTHER JOHN. 



cured the sultan is precisely the talisman which I 

 am about to recommend to your adoption, as the 

 only means of remedying bad health, and of pre- 

 serving that which is already good. 



Before I enter into particulars, I beseech you to 

 recollect what I have said to you in one of my for- 

 mer Letters ; viz. that if you admitted the truth of 

 what I then said, you would not afterwards be at 

 liberty to dispute the truth of what I am about to 

 say now ; any more than he who admits the truth of 

 the doctrines taught in the First Book of Euclid 

 can, without making a fool of himself, afterwards 

 deny the truth of those taught in the Second ; 

 because, if the one be true, the other, of necessity, 

 must be true. 



Before you proceed further, therefore, do me 

 the favour to re-peruse carefully and attentively 

 my Fourth and Fifth Letters. In doing this, 

 pay particular attention to the definition of life 

 the manner in which it is supported ; viz. by 

 the perpetual wasting and regeneration of the 

 body out of the blood to the definition of 

 health to the description of the functions per- 

 formed by the contractility and sensibility of our 

 organs to stimuli to the uses of the circu- 

 lation of the blood to the different characters 



