XX11 DEDICATION. 



familiar with chemistry will perceive, that the 

 only method which can lead to theiT final reso- 

 lution, namely, the quantitative method, has 

 been employed. 



The formulae and equations in the second 

 part, therefore, although they are not to be 

 viewed as ascertained truths, and as furnishing 

 a complete, or the only explanation of the vital 

 processes there treated of, are yet true in this 

 sense ; that, being deduced from facts by logi- 

 cal induction, they must stand as long as no 

 new facts shall be opposed to them. 



When the chemist shows, for example, that 

 the elements of the bile, added to those of the 

 urate of ammonia, correspond exactly to those 

 of blood, he presents to us a fact which is in- 

 dependent of all hypothesis. It remains for 

 the physiologist to determine, by experiment, 

 whether the conclusions drawn by the chemist 

 from such a fact be accurate or erroneous. 

 And, whether this question be answered in the 

 affirmative or in the negative, the fact remains, 

 and will some day find its true explanation. 



I have now to perform the agreeable duty of 

 expressing my sense of the services rendered 

 to me, in the preparation of the English edition 

 by my friend Dr. Gregory. The distinguished 

 station he occupies as a chemist ; the regular 

 education which he has received in the various 



