180 THE THYROID, THE THYMUS, AND THE ADRENALS. 



There is evidently a sound foundation for the belief that 

 phosphorus is the active constituent of the thymus gland. If 

 thyroid extract failed to improve the mental condition of the 

 ten cases collected by Cabot notwithstanding the increased 

 growth witnessed, it is either because the thymic gland in all 

 was structurally unable to respond to the increased oxidation 

 which the stimulated adrenals induced or because no thymus 

 gland was present. That this gland is absent in the vast ma- 

 jority of weak-minded, but not myxoadematous, children is 

 shown by the researches of Bourneville and Katz. That phos- 

 phorus is the main specific constituent of brain- and nerve- 

 substance is a recognized fact, fully sustained by physiochem- 

 ical data. That thyroid extract does not improve non-myx- 

 oadematous idiocy or weak-mindedness in children owing to the 

 absence of phosphorus in the organism is shown by the corre- 

 sponding effects it has on the skeleton of some cretins, as 

 observed by Telford-Smith, the bones, by their softness, show- 

 ing the absence of the hardening that calcium phosphate 

 procures. Finally, that the adrenals, through the normal oxi- 

 dation processes insured by them when adequately stimulated 

 by the thyroid secretion, sustain the activity of the thymus up 

 to its proper standard is shown by the experiments of Hoff- 

 meister and Eisenburg, in which removal of the thyroid of 

 various herbivorous animals caused bending of the legs. 

 The thyroid is thus able to stimulate the adrenals, and the 

 adrenals in turn can stimulate the thymus. But does the 

 thymus physiologically stimulate the adrenals? 



The fact that the thymus gland is but a temporary struct- 

 ure, one calculated to atrophy when its functions as a building 

 organ are accomplished, would seem to suggest that stimulation 

 of the adrenals is not one of these functions. If the deduc- 

 tions herein submitted are sound, it would appear to stand 

 prominently as a bone-forming organ and general phosphorus- 

 purveying organ from the time of the completion of its lym- 

 phadenoid elements during intra-uterine life until the final 

 elaboration of the skeletal frame-work, i.e., around the period 

 of puberty, its powers gradually receding as permanent or- 

 gans are developed. This conception of its purpose does not 

 appear to have suggested itself to anyone so far, but it is quite 



