86 CICATRIZATION OF WOUNDS 



lesions, the dimensions of which are too important. The 

 index of wounds decreases progressively until it reaches a 

 constant value, namely: o-02. It may decrease still further, 

 but we have no experimental facts to prove it. The largest 

 wounds which I was able to study did not attain 150 square 

 centimetres. But the maximum size of wounds affected by 

 the index 0-02 is not the same for every age. A man twenty 

 years old will cicatrize a wound of 150 square centimetres, 

 and over, with an index of 0-02, whereas the same index 

 characterizes a wound of 50 cm.^ on a man forty years old. 



Age, therefore, introduces important factors of retardation 

 into the rate of cicatrization. The table on page 85 shows the 

 extent of this action. 



I had established it to facilitate the calculation of the curves 

 by means of formula (4). It can be seen that all the values of 

 t-\-\^nt (where nt=T the age of the wound, and 1=4 days) 

 are calculated in advance for 24x4=96 days (last column). 

 Under these conditions the calculation was rapid. 



A 'family of curves' represented by Fig. 19 can be drawn 

 from this table. In the first place their geometric regularity is 

 impressive. It is striking that such clear quantitative relations 

 between the area of the wound, the age of the patient and the 

 index, can be obtained in a phenomenon as complex as 

 cicatrization. But the curves themselves are most instructive, 

 and propound new problems which we are incapable of solving, 

 for they depend on questions of a much more general order. 

 For instance, what is the signification of the highest curve 

 which corresponds to index 0-02? It signifies that all wounds 

 which give points located in the upper shaded region cicatrize 

 with the same index, or at any rate with an index very close to 

 0-02. It can be seen that above 150 cm. 2, age no longer seems 

 to play ^y part between twenty and forty years. But though 

 I have no proof of the fact, it is very probable that a wound of 

 this size should heal much more slowly in a man of forty. 

 There is no doubt that things are quite different on either side 

 of this curve and in my experiments I was unable to find 

 indices inferior to 002 except in pathological cases, or else 



