EXPERIMENTAL TECHNIQUE 7I 



S-S' 



• -7-'^"^^ ^^) 



I was thus in possession of a simple element of calculation 

 which expressed the quantity cicatrized per day between the 

 two measurements as a function of the total area of the wound 

 in question. One of two things must happen. Either the 

 wound would continue to cicatrize at the same rate, or else 

 other factors would intervene, and influence the velocity of 

 repair in proportion as the wound diminished. It was hardly 

 probable that the first hypothesis would be verified, for it was 

 too simple. Hence, there were few chances that my first 

 formula could be applied to the following period. In fact, I 

 observed a certain progressive divergence. It now behoved 

 me to study this discrepancy and to find a new factor the 

 variations of which would remain proportional to it. This 

 factor introduced into the formula would give it a constant 

 value from the beginning to the end of the phenomenon. In 

 case of success, the problem was solved, for it would then be 

 possible to calculate the curve from point to point. 



The difference between the biological method of approach 

 and the mathematical method borrowed from the physical 

 sciences is here clearly shown. The preceding chapter gave 

 the reader an idea of the multipHcity of the factors and of the 

 complexity of the problem. The solution had not yet been 

 found, because those who had studied it were too familiar with 

 the details of the phenomenon. Knowing a great many 

 physiological factors but ignoring their relative influence, they 

 did not dare eliminate them, and did not know how to take 

 them into account. They were paralysed by their knowledge. 



Like the botanist who could not see the forest because of 

 the trees, they could only consider the facts as a function of 

 microscopic biological elements with which they were familiar. 

 My ignorance of these elements freed me from the chains 

 which fettered them. Not knowing how to distinguish the 

 different species, I examined the forest from a distance, as a 



