THE SYMPATHETIC SYSTEM 359 



can be so obtained. Furthermore, it is questionable if it 

 is advisable to use partial extracts. 



We must admit then when we are trying by means of 

 organo therapy to make up the deficiency of an organ, this 

 organ is nearly always in a state of hypofunction of all its 

 products. It can be imagined that only one of the func- 

 tions will be affected. In these cases the affected organ 

 will only take the secretion which it needs. Finally, when 

 we only administer part of an organ we perhaps prevent 

 the patient reaping the benefit of the substances contained 

 in the parts which are not administered and which prob- 

 ably help to keep up a certain equilibrium which we should 

 avoid disturbing. 



This holds not only for partial extracts, but still more 

 for the definite products which we have isolated from- 

 certain organs. To be sure, there are only two of these so 

 far, namely, iodothyrin and suprarenalin. 



lodothyrin is not a chemical compound of definite 

 structure, for its iodine content varies and this is probably 

 also true of its activity. One fact is certain and that is 

 that there is no advantage in giving iodothyrin instead of 

 the total thyroid extract. 



Suprarenalin is a definite product; it has not only been 

 isolated but made synthetically. It is true that this syn- 

 thetic suprarenalin can be used instead of the total extract 

 of the suprarenal gland in certain cases. It still holds, 

 however, that this substitution is not advantageous in all 

 cases. Suprarenalin is easier to measure and preferable 

 for local applications and in certain general indications. 

 It is best, however, in treating endocrine disturbances to 

 use the total extract of the gland containing not only 

 suprarenalin but other substances, the nature of which is 

 still unknown to us, but whose value physiologically and 

 therapeutically is undeniable. Suprarenalin is the only 



