DUCTLESS GLANDS TAYLOR 705 



very potent secretion than the body needs. The symptoms of over- 

 dosage soon become evident. I shall not dwell upon the details of 

 this condition. There is of course increased metabolism, which re- 

 quires special methods for its detection. The most evident feature 

 i,s protruding eyeballs, though it is by no means certain that this 

 symptom can be laid at the thyroid's door. Indeed there is much 

 evidence that it can not. 



Ever since Murray showed that the functions of the thyroid were 

 due to an internal secretion and that this could be extracted, many 

 investigators have endeavored to isolate the active principle, or es- 

 sence, one might say, from the more or less crude extract which he 

 first obtained. As a result it was not long before some knowledge of 

 the chemical nature of the active principle wa,s gained. A few j^ears 

 ago this principle was obtained in pure form by Kendal, of Roches- 

 ter, Minn. He " dubbed " it thyroxin. It contains iodine, about 60 

 per cent combined with certain well-known organic materials. The 

 iodine radical is believed to be responsible for the growth-promoting 

 functions of the thyroid, and part of the organic radical (pyrrol) for 

 the effect upon metabolism. For if the iodine portion be broken off, 

 the remainder still increases the metabolic rate, yet it has now lost 

 its influence upon the metamorphosis of tadpoles. On the other hand, 

 if the pyrrol group alone is broken off, the material exerts it,s usual 

 effect upon the tadpole. 



Harrington, in England, within the last couple of years, has actu- 

 ally succeeded in manufacturing this material in the laboratory, that 

 is, in producing it artificially from its chemical constituents. It has 

 all the physiological properties of the natural product. But it, as 

 well as Kendal's thyroxin, is many times more powerful than Mur- 

 ray's crude extract ; an almost insignificant amount will produce the 

 most profound effects. It may be looked upon as the quintessence of 

 the thyroid juice, a superextract. 



The pituitary is another ductless gland which has just as important 

 duties to perform as the thyroid. But it is only a fraction of the 

 size of the thyroid. In man it is scarcely larger than a cherry and 

 lies like an Atla,s at the base of the brain with the huge hemispheres 

 heaped above it. And like Atlas, its responsibilities are great, for 

 if it is removed or destroyed the whole body is thrown into chaos. 

 It is cast into an abyss from which all the gods are powerless to 

 raise it; death follows inevitably and swiftly. As may be ,seen, this 

 gland is composed of two parts, which, though they are in intimate 

 contract with one another, have entirely different functions to per- 

 form. The two divisions are spoken of as lobes, the anterior and the 

 posterior. 



The pituitary has been a puzzle since ancient times. It is only 

 within recent years that a glimpse of its true functions has been 



