METAMORPHOSIS OF TISSUES. 125 



test against all conclusions and deductions which 

 now or at any subsequent period be derived from it in 

 opposition to the views developed in the preceding part 

 of this work, with which it has no manner of connexion. 

 The results here to be described have surprised me no 

 less than they will others, and have excited in my mind 

 the same doubts as others will conceive ; but they are 

 not the creations of fancy, and I give them because I 

 entertain the deep conviction, that the method which has 

 led to them is the only one by which we can hope to 

 acquire insight into the nature of the organic processes. 



The numberless qualitative investigations of animal 

 matters which are made are equally worthless for phys- 

 iology and for chemistry, so long as they are not insti- 

 tuted with a well-defined object, or to answer a ques- 

 tion clearly put. 



If we take the letters of a sentence which we wish 

 to decipher, and place them in a line, we advance not 

 a step towards tl^ discovery of their meaning. To 

 resolve an enigma, we must have a perfectly clear con- 

 ception of the problem. There are many ways to the 

 highest pinnacle of a mountain ; but those only can 

 hope to reach it who keep the summit constantly in 

 view. All our labor and all our efforts, if we strive to 

 attain it through a morass, only serve to cover us more 

 completely with mud ; our progress is impeded by dif- 

 ficulties of our own creation, and at last even the great- 

 est strength must give way when so absurdly wasted. 



20. If it be true, that all parts of the body are form- 

 ed and developed from the blood or the constituents of 

 11 * 



