THE SYMPATHETIC SYSTEM 355 



never proved by the English physiologists). Experi- 

 mental facts also led them to believe that this substance 

 had an elective action on the duodenal mucosa. 



Carnot and Deflandre have shown on their side that 

 tissues in formation or regeneration secrete substances 

 which stimulate the activity of similar tissues. For 

 instance, fetal bone marrow causes medullary hyperplasia 

 in anemias. 



From these experimental facts we are lead to believe 

 that this is a general rule for all the organs, and, if it is 

 so for healthy tissues, it is reasonably also probable in 

 diseased organs which have become impaired. 



We must remember that cells, in order to functionate 

 and repair their own structures need special products 

 which they manufacture themselves from various sub- 

 stances brought to them by the blood stream. Sick or 

 decreased in number, these same cells have their work 

 made easier if the various products which they need are 

 brought to them all made up. 



Whatever the interpretation, there is one important 

 fact from a practical point of view; that is, the elective 

 action exerted by the extract of an organ on a similar organ. 

 This fact has been proved experimentally and clinically. 

 Organo therapy is greatly helped by this fact. 



From this also result certain counter indications; when 

 an organ is defective by hyper secret ion, the use of a 

 homologous internal secretion must be forbidden. This 

 fact is well known; all we have to do is to remember the 

 action of thyroid in hyperthyroidism which in nearly 

 every case gives very bad results. There are, to be sure, 

 certain contradictory reports on this. Certain cases have 

 been reported which seemed to improve after receiving 

 small doses of thyroid. It is not impossible that a 

 physiological product might have a regulating action and, 



