THE THYROID APPARATUS 55 



and the chromaffioe tissue will be discussed in a later chapter. 

 The most important point in favour of the theory of antagonism, 

 is that provided by the hypertrophy of the thyroid and para- 

 thyroid glands, which is provoked in each by the suppression of 

 the other. But it must be borne in mind that anatomical hyper- 

 trophy is the result of functional hypertrophy; and that the hyper- 

 trophy of an organ can be ascribed to the suppression of its 

 antagonist, only where evidence is forthcoming of the manner in 

 which the one organ is excited to functional hyperactivity by 

 the suppression of another, the normal function of which is 

 antagonistic to it. A correlative hypertrophy of antagonistic 

 organs is, so far, unknown to us, and such a state of matters 

 does not seem very probable. 



Rudinger himself points out that the well-known variation 

 in intensity of the symptoms in Graves's disease makes it very 

 difficult to estimate exactly the beneficial effects of any therapy. 

 This does not enhance the value of Mossu and Charrin's experi- 

 ments and of the experiments with Moebius's serum, as evidence 

 in support of Rudinger's theory. And it has been shown, more- 

 over, that there is no proof of the difference, described by Vassale 

 and General! , between the clinical picture presented by tetany in 

 animals in which the thyroid is intact, and that presented by the 

 condition in animals which have undergone thyroidectomy v . 



The inevitable conclusion is, then, that a hypothesis of func- 

 tional antagonism between the thyroid and parathyroid glands, is 

 not supported by the evidence at our disposal. 



THE FUNCTION OF THE PARATHYROID GLANDS. 

 THE TETANY TOXIN. 



The first attempt to account for the tetany which follows 

 parathyroidectomy was the neutralization theory advanced by 

 Vassale and Generali. We have seen that these authors regarded 

 the thyroid as the organ in which the toxin was elaborated and 

 that, in its original form, their doctrine was untenable. Later 

 authors (Pineles, Pfeiffer and Meyer), however, are agreed that 

 a poisonous substance, the tetany toxin, is elaborated within the 

 organism, but that its exact source is unknown. 



Pfeiffer and Meyer endeavoured to demonstrate the presence 

 of this toxin in the blood of animals suffering from tetany. They 

 found that blood taken from dogs dying of tetany had a more 

 marked hasmolytic effect upon the blood corpuscles of guinea-pigs 

 than the blood of normal dogs. The observers do not attach any 

 particular significance to this result. On the other hand, they 

 emphasize the fact that the serum of tetanic dogs (in six out of 

 seventeen examined) was toxic to mice which had undergone 

 partial parathyroidectomy, causing tetany which, in some cases, 



