THE THYROID APPARATUS 53 



the new formation of tissue points to a hyper-function of the 

 gland, the wasting of the colloid to a hypo-function. If this 

 view is correct the same operation, namely, the removal of the 

 parathyroids, is able to produce conditions in the thyroid which 

 are opposed to one another. 



There are three directions, then, in which the evidence of 

 a functional relationship between the thyroid and the parathyroid 

 glands may be regarded as conclusive. In the first place, there 

 is the favourable influence of thyroid treatment in the tetania 

 parathyropriva of animals. In the second place we have certain 

 proof of hypertrophy of the external parathyroids after extirpa- 

 tion of the thyroid gland. And in the third place, there is the 

 hypertrophy of the thyroid gland, described by many authors, 

 which follows the removal of the parathyroids. These facts do 

 not, however, supply any definitive information concerning the 

 manner in which this interrelationship is effected. 



Vassale and Generali advanced the theory that toxic products 

 of metabolism are formed by the thyroid, and that these become 

 neutralized by the activity of the parathyroids. They based their 

 theory upon the fact that after parathyroidectomy the symptoms 

 are much more acute, the condition runs a more violent course, 

 and that death follows far more rapidly than after extirpation 

 of the entire thyroid apparatus. In the latter case, according to 

 this theory, both the toxin-forming and toxin-neutralizing agents 

 are removed. The explanation, however, can hardly be con- 

 sidered satisfactory. In the first place, it offers no solution of 

 the problem as to why animals from which the whole of the 

 thyroid apparatus has been removed, should yet develop fatal 

 tetany, seeing that the toxic agent is supposed no longer to be 

 present. In the second place, I was unable, in spite of repeated 

 experiments, to obtain any confirmation of the results described 

 by Vassale and Generali. I could not find any difference in the 

 intensity of the tetanic seizures, nor could I discover that animals 

 from which the thyroid apparatus had been removed in toto, 

 lived longer than those from which the parathyroids only had 

 been removed. Everyone who has had experience of post- 

 operative tetany knows how the clinical picture varies in regard 

 to intensity and duration, and will be careful how he allows these 

 factors to influence his conclusions in regard to the functional 

 relationship between the thyroid and parathyroid glands. 



What then is the inference which we may safely draw from 

 the results of these experiments ? First, that the hypertrophy of 

 the one group of organs after removal of the other is to be 

 regarded, upon general pathological grounds, as compensatory ; 

 and second, that a vicarious activity of the thyroid and para- 

 thyroids is to be assumed. 



It is remarkable that Rudinger employs these facts to support 

 a theory of antagonism between the thyroid and parathyroid 



