14 ENDOCRINE GLANDS 



of numerous cases of infantilism is sufficient evidence of 

 this. What are these substances? What is their mode of 

 action? We do not know. These are the harmozones of 

 Gley. (From the Greek I regulate, I direct). The study 

 of growth and its disturbances have been revolutionized 

 by these new ideas and it is to be hoped that in the future 

 our knowledge on this subject will increase considerably. 

 These chemical compounds which regulate development 

 are among those whose action must be most carefully 

 determined in order to use them therapeutically. The 

 action of thyroid and pituitary organo therapy in a great 

 many disturbances of growth shows what may be expected 

 once our knowledge of the harmozones of the thyroid and 

 the pituitary are better known. The recent investigations 

 on the anterior lobe of the pituitary and the regulating 

 action on growth by a substance, Tetheline, which can be 

 extracted from this lobe is at least very suggestive (Brails- 

 ford Robertson). 



The endocrine glands can, therefore, create, either nu- 

 tritive substances, such as, sugar, hormones, specific cel- 

 lular stimulants, such as, suprarenalin, harmozones 

 or regulating substances and finally we can, following 

 Gley, separate from the hormones, certain by-products or 

 par hormones, such as, urea, the product of the change of 

 toxic substances like ammonia or amino acids. It is also 

 possible to place next to the hormones, substances which, 

 instead of being stimulating, are depressing. These have 

 been designated by Schafer under the name of Chalone 

 (from the Greek I slow down). Perhaps this distinction 

 is too absolute; one internal secretion can be, according to 

 the case, either stimulating or depressing. 



The conception of the various glands of internal secre- 

 tion must be well understood before going into the study 

 of their pathology. It shows how complex is the mechan- 



