INFLUENCE OF AGE OF PATIENT 



89 



saw in the first chapter on cicatrization when speaking of 

 Carrel's experiments, that epithehzation is activated by the 

 proximity of the epitheHal edges. This enabled us to under- 

 stand the double part played by grafts of skin. It was there- 

 fore important to take this into account, the total gain on the 



s. 



cm 



4o 



30 



20 



JO 



4- & 12 J6 20 2^ 2& 32 3b UO Uk *& 5Z 5(> 60 



Time in days 



FIG. 21. RATE OF HEALING AS A FUNCTION OF THE SIZE OF THE 



WOUND 



date calculated being from twelve to sixteen days. Now, the 

 principal difference from a quantitative point of view between 

 such a wound and one that is round or square is that the peri- 

 meter, the length of the epitheUal edge, is increased with 

 respect to the area of the wound. It is therefore the shape 

 which plays a part, for no perceptible differences are observed 

 between wounds that are more or less indented, outside of 

 sudden but momentary accelerations such as the one mentioned 

 on page 82. 



I observed that the phenomenon of acceleration with respect 

 to the curve calculated by means of formula (4) only begins to 

 show slightly when the length is eight or nine times greater 

 than the width. When the ratio is equal to 10 (length 10 cm., 

 breadth i cm. for example), it becomes very apparent. It 



