DUCTLESS GLANDS — TAYLOR 699 



nervous system. It was the master tissue. It was the headquarters 

 staff which issued its orders to the various organs, and its authority 

 was believed to be supreme. With the discovery of the ductless 

 glands, an entirely new type of control of the bodily function was 

 brought to light. Their influence, if less evident than that of the 

 nervous system, is nevertheless just as important in their own par- 

 ticular sphere. 



The internal secretions have authority over slowly moving proc- 

 esses, sucli" as the development of particular organs, the growth of 

 the body as a whole, and the metabolism of food materials — processes 

 measured by hours, months, or years; whereas the nervous system 

 presides over those rapid processes of thought — muscular movement 

 and the external secretion of glands — processes measured by frac- 

 tions of seconds (or minutes). 



There are man}'^ sides from which the functions of the ductless 

 glands may be viewed. I might, for instance, discuss them in their 

 relation to character or to personality or heredity, or even to morality 

 or criminality ! And there is little doubt but that they have an 

 influence upon some or all of these, but so far science has been unable 

 to place a finger upon anything very definite. Or I might discuss 

 them in their relation to our " decline into the vale of years," as the 

 poet with such a pleasant euphemism refers to old age. But this 

 side of the question, which has received a great deal of attention in 

 France and on the Continent, is so befogged by pseudoscience and 

 beset with quackery that I would rather leave it alone. I prefer to 

 take up more definite and known effects, effects that can be proved 

 by direct observation or experiment, and to avoid the more specula- 

 tive side of the subject, which, after all, is no stranger than the truth. 



Several methods have been and are still made use of to unravel the 

 mysteries of the endocrine glands. In the first place, extracts of the 

 gland tissue may be prepared which may then be injected into ani- 

 mals and a study made of their effects. Secondly, particular glands 

 may be removed from animals and the subsequent life history of 

 these animals watched, taking careful notice of their subsequent de- 

 velopment, growth, or any unusual symptom. Or, thirdly, we may 

 study diseases in the human subject in whom a particular gland is 

 known to be deficient or overactive. 



I shall consider first a gland with which everyone to some extent 

 is familiar. This is the thyroid, which lies beneath the muscles of 

 the neck embracing the larynx. When enlarged inordinately, it con- 

 stitutes the condition known as goiter. All the methods of investi- 

 gation which I have mentioned were used in the study of the thyroid 

 before any clear idea of its functions was formed. 



A certain slight enlargement of the thyroid above the average is 

 an adjunct to feminine beauty. Indeed, one of the older anatomists 



