EFFECTS OF PARATHYROIDECTOMY 61 



As a result of these experiments attempts have been The para- 



1 . . thyroids and 



made to base the causation of many conditions associated the calcium 

 with tetanoid spasms on lesions of the parathyroids. It metabolism. 

 must, however, not be forgotten that the parathyroids 

 are only one of the many regulators of the calcium 

 metabolism. It may be mentioned in respect of these 

 observations that the work of Ringer and Buxton 1 proved 

 conclusively many years ago that the calcium salts con- 

 trol the excitability of skeletal muscle, probably through 

 the neuromuscular junctions ; consequently it follows 

 that with insufficiency of lime salts in the blood and 

 tissues excitability amounting to tetany may occur. 



Now, the connexion of these findings with the genital The genital 



. i.ii functions and 



functions, which are so largely concerned with the the para- 

 calcium metabolism, appears obvious from what has yr01 s * 

 already been said ; but extremely little direct investiga- 

 tion has been made to define the relation of the para- 

 thyroids to the genital functions. Silvestri 2 has stated 

 that castration delays the onset of tetany after para- 

 thyroidectomy, but Massaglia 3 , Meyer 4 and others have 

 been unable to obtain the same result. It will be re- 

 membered that castration has been found to prevent 

 tetany in cats from which the thyroid with most of the 

 parathyroidal tissue had been removed (p. 51). It may 

 be that in these circumstances a considerable calcium 

 retention is produced, for apparently the parathyroids 

 and gonads — especially the ovaries — are antagonistic in 

 their relation to the calcium metabolism. 



However, until more work has been done on the 

 histology and physiology of the parathyroids at different 

 ages and in different circumstances, especially in the 

 female, we cannot discuss further the relationship of 

 these organs to the genital system with any advantage. 



1 Ringer, S., and D. W. Buxton, Journ. Physiol., 1887, vol. viii, 

 pp. 15 and 288. 



2 Silvestri, T., Policlin. Sez. Prat. Roma, 1910, vol. xvii, p. 1571. 



3 Massaglia, A., Oaz. Delgi. Osped. e. delle Clin. Milano, 1911, 

 vol. xxxii, i, p. 422. 



4 Meyer, 11, Beit. z. Klin. Chirurg., 1914, vol. xciv, p. 373. 



