FUNCTIONS OF DUCTLESS GLANDS. 



4*5 



development and growth, and when, at the period of 

 puberty, the development of the body may be said to be 

 complete, the gland wastes, and finally disappears. The 

 thyroid gland and supra-renal capsules, also, though they 

 probably never cease to discharge some amount of function, 

 yet are proportionally much smaller in childhood than in 

 foetal life and infancy ; and with the years advancing to 

 the adult period, they diminish yet more in proportionate 

 size and apparent activity of function. The spleen more 

 nearly retains its proportionate size, and enlarges nearly as 

 the whole body does. 



The function of the vascular glands seems not essential 

 to life, at least not in the adult. The thymus wastes and 

 disappears ; no signs of illness attend some of the diseases 

 which wholly destroy the structure of the thyroid gland ; 

 and the spleen has been often removed in animals, and in 

 a few instances in men, without any evident ill-consequence. 

 It is possible that, in such cases, some compensation for 

 the loss of one of the organs may be afforded by an in- 

 creased activity of function in those that remain. The 

 experiment, to be complete, should include the removal of 

 all these organs, an operation of course not possible without 

 immediate danger to life. Nor, indeed, would this be 

 certainly sufficient, since there is reason to suppose that the 

 duties of the spleen, after its removal, might be performed 

 by lymphatic glands, between whose structure and that of 

 the vascular glands there is much resemblance, and which, 

 it is said, have been found peculiarly enlarged when the 

 spleen has been removed (Meyer). 



Although the functions of all the vascular glands may 

 be similar, in so far as they may all alike serve for the 

 elaboration and maintenance of the blood, yet each of them 

 probably discharges a peculiar office, in relation either to 

 the whole economy, or to that of some other organ. 

 Respecting the special office of the thyroid gland, nothing 

 reasonable can be suggested ; nor is there any certain 



