THE THYROID APPARATUS 47 



glands as regulatory organs whose task it is to maintain the 

 balance of neuro-muscular activity. This view is illustrated by 

 the accompanying diagram, in which parallel conditions originat- 

 ing with the thyroid gland are also included. 



Chvostek (1908) made a minute analysis of the clinical sym- 

 ptoms of Myasthenia gravis. He rejected the hypothesis that 

 this condition is primarily of nervous or muscular origin, and is 

 of the opinion that, in all essential points, myasthenia and tetany 

 are diametrically opposed. " They have the same relationship to 

 one another that the negative has to the photograph," and yet 

 they have certain points in common which make it impossible to 

 deny them a common origin. Chvostek believes that tetany is 

 produced by hypo-function of the parathyroids, while hyper- or 

 dysfunction gives rise to myasthenia. The originating cause of 

 this disturbance of function may lie in changes which take place 

 either within the gland itself, or in the centres or channels by 

 which its function is regulated. Thymus persistency, which so 

 frequently accompanies myasthenia, has no pathogenic signifi- 

 cance : it merely points' to the existence of a constitutional 

 anomaly, favourable to the manifestation of symptoms of func- 

 tional parathyroid derangement. 



THE THERAPEUTICS OF TETAXIA PARA- 



THYROPRIVA. 



Once we are assured that tetany results from the suspension 

 of function of the parathyroid glands, the therapeutics of the 

 condition become much simplified. The object of any therapy 

 must be to restore to the organism the function of the gland which 

 has become incapacitated. The simplest method is by trans- 

 plantation, and before the parathyroid origin of tetany was 

 recognized, the condition was frequently treated by thyroid 

 transplantation. But the subjects of experiment were invariably 

 animals in w r hich, as we now know, the implantation of the 

 thyroid necessarily included the implantation of the parathyroids. 



In 1884 Schiff succeeded in keeping a thyroidless dog alive for 

 some time by implanting fresh thyroid glands in the abdominal 

 cavity. V. Eiselsberg (1892) showed more positively that the 

 thyroid gland, when implanted in the abdominal fascia or in the 

 peritoneum of cats, healed in and prevented the occurrence of 

 tetany. When the healed-in tissue was removed, tetany followed 

 and the animal died. 



Enderlen (1898) recognized the significance of the para- 

 thyroids and in the experiments which he carried out with clogs 

 and cats he found that these glands preserved their structure 

 after implantation better than the thyroid. 



Following E. Payr's method with the thyroid, I have grafted 



