300 THE DUCTLESS GLANDS 



suspect not only that the thyroid receives, under certain 

 circumstances, a large share of the blood which would otherwise 

 have supplied the brain, but also that the secretion of the 

 former organ bears some essential relation (which chemistry 

 may hereafter elucidate) to the specific nutrition of the latter ; 

 that the gland whether or not it appropriates its elements in 

 the same proximate combination as the brain does may, 

 at all events, affect in a precisely similar degree the chemical 

 constitution of the blood traversing it, so that the respective 

 contents of the thyroid and cerebral veins would present 

 exactly similar alterations from the characters of aortic blood. 

 Finally, I should suppose that these actions occur only or 

 chiefly during the quiescence of the brain, and that when this 

 organ resumes its activity, the thyroid may probably render 

 up again from its vesicles to the blood, in a still applicable 

 form, those materials which it had previously diverted from 

 their destination." 



Writing a few years later (1849-1852), Handfield-Jones still 

 thought it necessary to criticize adversely the various ancient 

 theories which supposed the thyroid to bear some functional 

 relationship to the larynx. He says that there seems no doubt 

 that the relative position of the thyroid to the larynx is quite 

 unimportant, so far as the function of the organs is concerned. 

 This is borne out by the variations of its site, which occur in 

 birds, and by the results of morbid action, since prodigious 

 goitre does not induce disease of the larynx, except in a me- 

 chanical way i.e., by injurious pressure. 



Referring to Simon's theory, Handfield-Jones remarks, 

 " It is the only one yet promulgated which can be said to 

 be even probable." He does not, however, declare himself 

 an adherent to the theory, of which, in fact, he offers several 

 criticisms. 



K. Extirpation Experiments upon Mammals 



The earliest extirpation experiments upon animals appear 

 to have been performed by Raynard. This observer reports 

 that the treatment of goitre in dogs can be carried out just 

 as in man. Complete removal of the thyroid was successfully 

 carried out in dogs of medium age and in old dogs, but in young 

 animals death occurred within a few days. The post-mortem 

 examination did not reveal the cause of death. 



