178 THE THYROID, THE THYMUS, AND THE ADRENALS. 



found that during thyroid treatment the rapid growth of the 

 skeleton leads to a softened condition of the bones, resulting 

 in a yielding and bending of those which have to bear weight; 

 and, as cretins under treatment become more active and in- 

 clined to run about, this tendency to bending has to be guarded 

 against/ 7 After referring to the experiments of Hoffmeister in 

 'rabbits and those of Eisenburg in sheep and goats in which 

 bending of the legs was caused by removal of the thyroid, he 

 adds: "While in rickets, however produced, there is perverted 

 and delayed ossification resulting in softening and bending of 

 the bones, under thyroid treatment in cretinism there is rapid 

 resumption of growth in the skeleton, leading to softening, 

 which is most marked in the long bones and at the epiphyses." 

 That we are dealing here with an absence of phosphorus and 

 that the calcium phosphate serves to harden the bones con- 

 currently with their growth seem obvious. 



But why does this not occur in all cases? Simply through 

 the fact, ascertained by Marie, 59 that the thymus is almost 

 always persistent in cases of cretinism. When thyroid extract 

 is administered, therefore, the increased oxidation procured by 

 stimulating the adrenals also enhances thymic activity, and the 

 assimilation of phosphorus is increased in proportion. This is 

 proven by the experiments in animals by Hoffmeister and 

 Eisenburg, referred to by Telford-Smith. If removal of the 

 thyroid caused bone-softening in these, it is because in the 

 light of our conception of the process the adrenals were ren- 

 dered inadequate, and, oxidation being impaired in proportion, 

 the thymus also failed functionally. 



This process, however, involves the need, in the structures 

 of the thymus gland, of a metabolic process culminating in the 

 production of an internal secretion laden with phosphorus- 

 containing bodies. Quotations from a study of the nucleins 

 and nucleoproteids in their relation to internal secretion by 

 Chittenden 60 will serve to enlighten us: "The manufacture of 

 the specific substances which give character to the various 

 internal secretions is obviously a function either of special 



59 Marie: Bulletin et Memoires de la Societe Medicale des H6pitaux de Paris, 

 p. 136, 1893. 



00 Chittenden: Boston Med. and Surg. Journal, August 20, 1896. 



