102 WHAT IS LIFE 



sion and even on the last occasion the process of 

 reconstruction took place with the same rapidity 

 as it had done on the first. Spallanzani calculated 

 that during these three months the animal under 

 experiment had made for itself no less than 647 

 new bones, not to speak of all the muscles, nerves 

 and arteries which formed with the bones in 

 question the various parts which were restored. 



Spallanzani also found that the salamander 

 could regenerate its upper and its lower jaws if 

 these were snipped off. It is obvious, therefore, 

 that an animal of quite high position in the scale 

 of nature may possess very remarkable powers of 

 repair. It will be noticed that there is one very 

 important difference between the phenomena ex- 

 hibited by the vertebrate and by the invertebrate 

 and that is that the former cannot be so divided as 

 to constitute from it two complete forms. There is 

 then a limitation of the powers possessed by the 

 more lowly form. On the other hand its recon- 

 structive abilities are much greater than those 

 which are possessed by any mammal. The mammal 

 can heal up a wound if that wound is not of so 

 serious a character as to cause death, but it cannot 

 re-grow even a joint of a lost limb, much less repro- 

 duce the entire member as the salamander or newt 

 can. 



A further remarkable experiment has been 



