64 CICATRIZATION OF WOUNDS 



The presence of the small centre of infection had sufficed to 

 bring the lower edge of the wound almost back to its original 

 dimension. 



4. Cicatricial Period. The scar left by a large wound is 

 proportionally smaller than that left by a small wound. A 

 wound 66 millimetres long left a scar of 22 millimetres, whilst 

 a wound 26 millimetres long, on the same animal, left a scar 

 of 13 millimetres. In the first case the scar represents one 

 third, and in the second case, one half of the size of the 

 original wound. In small wounds of about 10 milUmetres, 

 the scar is almost as extensive as the wound. When the 

 epidermization is ended and the wound healed, the scar 

 begins to spread and distends itself (see Fig. i) so that points 

 A and B tend to come back to their original position. This 

 last period is very long (several months) and completes the 

 regeneration of the lesion. 



In brief, the mechanisms of the phenomenon of cicatrization 

 are co-ordinated in such a fashion that the reparation is 

 continuous. For dogs, the processes are adapted to the quick 

 healing of small and medium-sized wounds, not wider than 

 40 millimetres. In a wound 30 to 40 miUimetres wide the 

 contraction is very efficient, and in a short while the edges 

 are brought to within 10 or 15 millimetres of each other, 

 a distance which is favourable to epidermization. Thus, at 

 the moment when the rate of reparation through contraction 

 tends to slow up, epithelization starts in and the work of 

 regeneration continues without interruption, but by means 

 of a different mechanism. 



I have dwelt at length on these preliminary experiments 

 because it was necessary for the reader to know the subject 

 and to be familiar with the terminology. What precedes 

 suffices to explain the complexity of the phenomenon which 

 had to be translated quantitatively by the simplest possible 

 formula. The problem which I had to solve was perfectly 

 well defined. It consisted in finding a method which would 

 permit us to predict in advance the dimension of any kind of 

 wound at the end of 4, 8, 15, . . ., jc days and, consequently. 



