INFLUENCE OF SIZE OF WOUND 99 



were then called the a, (3, and y rays remained immutable. The 

 conclusion, without possible doubt, was that this was not a 

 chemical phenomenon but a phenomenon of atomic dis- 

 integration. The same is true of the photo-electric pheno- 

 menon, known as the Hertz-Hallwachs effect, which consists 

 in the discharge of a conductor of polished zinc, electrically 

 isolated and on which falls a beam of ultra-violet light. By 

 varying the temperature it was proved that this was purely an 

 electronic phenomenon and not a result of combination or 

 decomposition. 



The problem was less easy to solve in the case of cicatriza- 

 tion, for it was necessary to work over a range of 10° or 15° C. 

 This immediately eliminated all 'warm-blooded' animals, 

 which could be more correctly called 'thermo-stable' animals. 



But there are a quantity of so-called 'cold-blooded' animals. 

 These animals are not characterized by the fact that their 

 blood is cold, which does not signify much, but by the fact 

 that their blood maintains itself approximately at the tem- 

 perature of the surrounding medium. The reader is aware 

 that insects, fish, reptiles, and batrachians belong to this class. 

 They are deprived of the property of maintaining their 

 temperature constant. For evident reasons it was impossible 

 to work on insects or fish. But in the class of reptiles, alliga- 

 tors and crocodiles were particularly indicated, for they can be 

 kept without difficulty at temperatures varying between 10° 

 and 40° C. At 10° C. they are somnolent and in a state of 

 latent life. At 40° C. they are in full activity. 



Square, easily measurable wounds were cut out on the 

 abdomens of young Florida alligators and curves were estab- 

 Ushed. The animals were kept at temperatures constant from 

 beginning to end of each experiment, but variable for each 

 new wound. 



It was found that the rate of cicatrization varied in the mean 

 ratio of 2-12 (extremes: 2-47 and i-88) when the temperature 

 was raised or lowered by 10° C. For instance, at 23° C, a 

 crocodile weighing 314 grams cicatrized a wound of 1-3 square 

 centimetres in 29 days and the same animal at 38° C. (that is, a 



