82 THE VITAMINES 



nutrition. By means of frequent sub-cultures, Carrel prevented the 

 nutritive substances from becoming exhausted. That this had to be 

 resorted to frequently in order to keep a fragment of tissue alive for 

 a long while, shows perhaps that the conditions for growth could 

 have been better chosen. 



In this respect, the method may be applicable to a new field of 

 work. We have in mind particularly Carrel's antiseptic method 

 of treating wounds, which came into use during the war. It is 

 apparent that the organism suffering from shock and other complica- 

 tions could not be in the best nutritive condition; and in the wounded 

 tissue itself, through the disturbance of the blood circulation, con- 

 ditions could not be the most favorable. For these reasons, it would 

 be of interest to apply to the treatment of the wound, those facts 

 that have been learned in the study of the composition of nutritive 

 fluids best suited for the tissues. Practically, this could be brought 

 about by the substitution of the antiseptic solution by a nutritive 

 solution from time to time, with the possibility that the wounded 

 tissue could be nourished and the process of healing hastened. 



The method of Carrel (225) is as follows : Under appropriate con- 

 ditions, tissue fragments, and pieces of tumors too, may be grown for 

 more than four months, during which the tissue shows growth and 

 peripheral expansion. The tissue (226), antiseptically prepared, is 

 placed in a plasma diluted with J to \ of its volume of distilled 

 water. For this purpose, it is best to use the plasma of the animal 

 under investigation or that of a homologous animal. In from 3 to 

 4 days, the tissue culture (Carrel (227), Carrel and Burrows (228)) 

 is placed for a few minutes in Ringer's solution and then transferred 

 to a fresh plasma. Some tissue cultures have been kept alive for 

 four and a half months, having been transferred as above 48 times. 

 A fragment of heart continued to beat after 140 days. Only embry- 

 onic tissues and tumors could grow in an artificial medium (Locke's 

 solution, agar and bouillon). In a later work, Carrel (229) investi- 

 gated in greater detail the influence of tissue extracts and body fluids 

 (as did Walton (230) too), and found that they increased the growth 

 of connective tissue in particular from 3 to 40 times. This was the 

 case especially with embryonic spleen extracts, and it was consider- 

 ably smaller with greater dilutions. It was true only of the same 

 type of animal, and the action of the extracts was weaker on heating 

 to 56C. and entirely dissipated at 70C. The active substance 



