1* ENDOCRINE GLANDS 



tachyphylaxis, that is, a rapid immunization against the 

 toxic action of certain organs. This last suggestion, to 

 which we are indebted to Champy and Gley, adds to the 

 complexity of investigating the mode of action of extracts 

 of organs. There are certain extracts which will only give 

 a reaction when given in extra physiological doses, the 

 doses used representing the total weight of the organs from 

 which these extracts are obtained. This is the case of 

 pituitrin which is used in relatively large doses and whose 

 efficacious action cannot be contested. 



All these facts show how careful we must be in inter- 

 preting the therapeutic results obtained, and, as Gley has 

 said, "the real criterion of the function of an internal se- 

 cretion is the presence of a specific product in the venous 

 blood of a gland." This criterion so far has only rarely 

 been complied with. This does not mean that we must 

 dismiss all the facts revealed by therapy and experimen- 

 tal investigations on the extracts of these organs. It 

 simply means that we must be very critical and not 

 jump at conclusions. 



EXPERIMENTATION ON ANIMALS often have confirmed 

 the observations obtained with the extracts. All that is 

 necessary is to recall the results of experimental thyroid- 

 ectomy and para thyroidectomy, of hypophysectomy, and 

 castration to establish the fact that these glands play a 

 physiological part in the organism and that alterations in 

 these glands will result in pathological conditions, which 

 we run across clinically. 



THE NATURE OF THESE SECRETIONS is still uncertain. 

 It was admitted early by Gley and others that these 

 glands produced substances having a specific action on 

 other glands or tissues; iodothyrin for instance, which is 

 secreted by the thyroid, has a direct action on meta- 

 bolism, and its absence will cause disturbances in nu- 



