THE ESSENTIAL DUCTLESS GLANDS 229 



of the life of the body the growth, the sexuality, the 

 emotions, the immunity one wonders whether, after 

 all, this avalanche of literature is keeping pace with the 

 interest that the subject deserves. 



In a short essay, limited in scope and space, one can- 

 not go into the details of this subject. Those who look 

 for details are referred to the substantial works of A. 

 Biedl, "The Internal Secretory Organs; Their Physi- 

 ology and Pathology;" Sajous' "Internal Secretions 

 and Principles of Medicine ;" Swale Vincent's "Internal 

 Secretion and the Ductless Glands ;" Falta's "Ductless 

 Glandular Diseases;" Harrower's "Practical Hormone 

 Therapy," and numerous other works. In this essay 

 we will, therefore, merely outline rather roughly the 

 salient points regarding some of the endocrine glands 

 and their influence upon the organism and conclude 

 with a brief mention of some of the potentialities that 

 those glands hold out to us in the nearest future. 



THE HORMONE PRODUCING ORGANS 



As their name implies, the ductless glands are organs 

 whose products, called hormones, have no outlet into 

 the free surfaces of the organism, like ordinary glands 

 do, but instead find their way directly into the blood 

 stream, which, laden with such hormones, exerts its 

 specific influence upon the living organism. Hence the 

 term, "internal secretion." The branch of medicine 

 that makes a study of the ductless glands and their in- 

 ternal secretions is called "endocrinology." The most 

 known, because the most studied glands of this type, 

 are the thyroid, parathyroids, adrenals, pituitary and 

 gonads (testicles and ovaries). Others, perhaps less 

 well known in their action, are the thymus, pancreas, 

 spleen and pineal gland. 



It seems that Nature, in her wise ways, fully appre- 

 ciated the importance and value of these small organs 

 in placing them in inaccessible corners of the organism, 



