The Salivary Glands, Stomach and 

 Intestines as Endocrine Organs 



FRED C. KOCH 



CHICAGO 



Introduction 



Status of the Problem and Nature of Evidence. In this chapter the 

 aim has been to give a critical review of the available published researches 

 on this subject taken in its broadest sense. One does not have to go 

 very far in his search for good physiological evidence before he is be- 

 wildered with the numerous conflicting reports, not only in the clinical 

 phase of the subject, but particularly in the more scientific and experi- 

 mental studies. The first desideratum is the actual evidence that certain 

 or all of these organs do possess true endocrine functions. Unlike the main 

 evidence obtained in such cases as the thyroid, suprarenal, parathyroid 

 and pituitary, that is, the observed effects after removal of these glands, we 

 here have been trying to establish endocrine functions more particularly 

 upon the physiological effects resulting from the injections of various 

 extracts prepared from the organs in question. When the effects produced 

 have been more or less specific, as to nature and site of response, and par- 

 ticularly more or less quantitatively specific, as to origin of extract, then 

 the evidence has been taken as indicative of a true hormone action. It is 

 evident, of course, that unless the experimental data indicate a quantita- 

 tive specificity, as to site of action and origin of extract, that the evidence 

 is very unsatisfactory indeed. Even if the facts thus obtained are in- 

 dicative in a positive direction, the evidence is by no means conclusive, in 

 that the conditions existing during the experimental observations are by 

 no means representative of normal physiological processes. It is a very 

 different matter, on the one hand, to introduce into the blood stream sub- 

 stances which are obtained by the various extraction methods from an 

 organ, and, on the other hand, to prove that the same substance or sub- 

 stances are really normally present in the blood flowing from the organ in 

 question. The extraction method may produce substances entirely foreign 

 to the blood stream. The other main line of experimental evidence which 

 has been obtained is based on the transfusion or injection of blood where 



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