JUGGLING WITH LIFE 



generally haunt secluded crevices and lie in wait for 

 their food, consisting largely of insects or small 

 worms and the like. The loss of a leg might not 

 jeopardize the life of such a creature in any such 

 degree as the life of a mouse must be jeopardized 

 by a similar loss. Natural selection, therefore, may 

 preserve the capacity to grow new members in the 

 case of a cold blooded animal; through the same 

 agency the capacity has been lost in the case of warm 

 blooded animals. 



But whatever the explanation, the fact remains, 

 and we should think it almost miraculous were a 

 mammal observed to grow a new leg in place of one 

 that has been amputated. 



Very recently, however, Dr. Alexis Carrel, of the 

 Rockefeller Institute, New York, has shown that the 

 lost members of a higher animal may be replaced 

 by the substitution of a new member through a sur- 

 gical procedure. He has amputated the leg of a dog, 

 for example, and replaced the member with a closely 

 similar one taken from another dog; and has seen 

 the new member grow into place and become a part 

 of the body of its new host. 



Dr. Carrel has similarly transplanted various in- 

 ternal organs, including the kidneys, from one animal 

 to another, and caused them to take root, as it were, 

 and perform their normal functions. The success of 

 his experiments is due largely to his introduction of 

 a new method of uniting arteries and veins, whereby 

 they are so cleverly sutured together that scarcely 

 a trace of the point of union remains when the wound 

 has healed. In recognition of the importance of this 



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