48 THE PROTEOMORPHIC THEORY AND THE NEW MEDICINE 



From the present standpoint, the thing of chief interest is 

 that Dr. Carrel's observations show that there is a specific quality 

 about the tissues of an animal that is profound and individual. 

 The kidney of a cat seems to perform identically the same func- 

 tion as the kidney of a dog. But one cannot be substituted for 

 the other in these experiments in transplanting members. The 

 kidney of a dog may be transferred to another dog; the kidney 

 of a cat to another cat ; but the two must not be interchanged. 



Even where the organ experimented with is so simple as the 

 tube of an artery, it is with difficulty that an exchange between 

 animals of different species may be effected. To all casual obser- 

 vation, and even to close observation with the microscope, the 

 artery of a cat seems identical with that of a dog; but there is 

 a deep-seated chemical difference which makes itself felt if, for 

 example, a section of cat's artery is made to replace an exsected 

 portion of the artery of a dog. 



It was a foregone conclusion, therefore, that the attempt re- 

 cently made by a Berlin surgeon to replace a diseased human 

 kidney with the kidney of a monkey would be a failure. The 

 surgeon of the future will doubtless replace diseased kidneys 

 and other vital organs with normal ones, but the substituted 

 organs will be taken from human subjects say from the vic- 

 tims of accidents, or from executed criminals. 



TRACING BLOOD RELATIONSHIP 



The specific quality which thus pervades every tissue of an 

 organism so that the remotest cell of a cat, for example, has 

 some quality of felineness that distinguishes it from a cell of 

 any other species of animal extends its mysterious influence so 

 comprehensively that it includes not merely every fiber of the 

 organism, but every drop of blood in an animal's body. 



The proof of this has been given by Professor G. H. F. Nut- 

 tall, the American biologist, now of the University of Cam- 

 bridge, in the series of experiments just referred to. 



Professor Nuttall has developed a system of blood testing of 

 such delicacy as quite to transcend the bounds of microscopic 

 examination or of any chemical methods hitherto known; and in 

 so doing has found a method of testing the relationships of dif- 

 ferent tribes of animals that seems little less than magical. 



The tests show, for example, that man is more closely related 

 to the old-world monkeys than to the monkeys of the new world ; 

 our closest relatives being the chimpanzee, the gorilla, and the 

 orang in the order named. Similarly the relationships between 

 different members of the dog family, the cat family, and the 

 like, are traced. Thus the hyena appears to be to some extent 



