PARATHYROID GLANDS ' 659 



and Sprunt (1921) observed the occurrence of manifest tetany during 

 paroxysmal hyperpnea in a neurotic patient convalescent from lethargic 

 encephalitis, apparently the first observation of tetany due to a pathologi- 

 cal (non-experimental) hyperpnea. (Fig. 15.) From now on it will 

 be important to watch for manifest tetany and to test for latent signs of 

 tetany in the various pathological hyperpneas that are met with clinically. 



9. Unitary Conception of Tetany 



As has been repeatedly hinted in the preceding pages, the conception of 

 a unitary pathological-physiological basis, namely, a parathyroid gene- 

 sis, for all forms of human and animal tetany has steadily grown in favor, 

 until now it has become widely accepted, though still with reservations by 

 the more conservative. 



It was for the tetany following operations upon goiter that the founda- 

 tion was laid, stone by stone, for the absolute proof of a. parathyrogenetic 

 origin. The building stones of this proof form an interesting series, as 

 follows: (1) the clinical observation of the occurrence of tetany after 

 strumectomy ; (2) the discovery of the parathyroid glands ; (3) the demon- 

 stration that parathyroidectomy alone causes tetany, that thyroidectomy 

 alone causes myxedema, and that thyroparathyroidectomy causes tetany 

 plus myxedema; (4) the finding of parathyroid glands in the mass re- 

 moved in strumectomy in cases in which outspoken tetany occurred; (5) 

 the absence of tetany in complete thyroaplasia, if the parathyroids be nor- 

 mal; (6) the absence of tetany on removal of the middle portion of the 

 thyroid gland in so-called "tongue goiter"; (7) the relatively frequent 

 appearance of tetany on removal of the lateral lobes of the thyroid, while 

 leaving the isthmus intact; (8) the relief of tetany by the administration 

 of parathyroid substance; and (9) the cure of tetania strumipriva by 

 means of transplantation of the parathyroid gland. 



Through the edifice thus gradually erected the parathyroid origin of 

 tetania strumipriva was made absolutely clear ; but there has been some 

 hesitation on the part of clinicians in accepting the doctrine that all the 

 other forms of tetany are also of parathyroid origin, for in these other 

 forms it is harder to prove that there has been an abolition or a diminution 

 of the parathyroid functions. Opportunity for the pathological-histological 

 examination of parathyroid glands in forms of tetany other than tetania 

 strumipriva are not common. In the few cases in which the parathyroids 

 have been examined post mortem, pathological-histological changes have 

 sometimes been found, though not always ; and those who assume a para- 

 thyroid origin for all forms of tetany have been compelled to fall back, 

 in many cases at least, upon a functional defect of the parathyroid glands 

 without demonstrable histological lesion. Comparative clinical studies, 



