28 The Endocrine Organs 



There seems, however, to be no doubt that cases of tetany benefit by 

 the administration of thyroid extracts, although the tetany cannot be cured 

 by such administration. It is unlikely that the effect is due to the minute 

 proportion of parathyroid substance in these extracts. 



Mrs Thompson has described the development of colloid vesicles in the 

 pars intermedia of the pituitary after parathyroidectomy, and has con- 

 cluded that this is a vicarious effect — but it must be remembered that 

 there are great individual variations in the number of such vesicles in the 

 pituitary, and that some animals exhibit a very large number even normally. 

 Most other authors have failed to substantiate any change in the pituitary 

 after parathyroidectomy alone, although there are marked changes after 

 thyroidectomy. 



Very little that is definite has been substantiated regarding the rela- 

 tions of the parathyroids with the suprarenals, or with the internal secret- 

 ing functions of the pancreas or the generative glands. It has, how- 

 ever, been affirmed (Guleke) that removal of the suprarenals prevents the 

 appearance of tetany after parathyroidectomy, but only when the thyroid 

 is included in the removal. And, on the other hand, that adrenalin 

 injection will bring on a fit of tetany in a parathyroidectomised animal. 

 These effects are produced no doubt through the nervous system, and point 

 to a certain antagonism between suprarenal and parathyroid. 



Gozzi has described degenerative changes in the liver-cells as a result of 

 parathyroidectomy, but regards them as secondary to the general effects on the 

 organism as a whole. 



