THE PAEATHYEOID GLANDS 515 



Further, to prove that the parathyroids were responsible for the after 

 effects and not any damage to the thyroids, in one dog they removed two 

 small portions of each lobe of the thyroid, leaving the parathyroids intact ; 

 no symptoms followed. One circumstance which seemed to surprise them 

 was that death appeared to follow more certainly and more rapidly than 

 after the complete thyroparathyroid operation. 



In a further communication, in discussing various hypotheses to ex- 

 plain the results of simple parathyroidectomy, Vassale and Generali draw 

 attention to the fact that Lusena had confirmed their statement that extir- 

 pation of the parathyroids alone is more rapidly fatal than thyroparathy- 

 roidectomy, and, further, to his observation that, when a dog is in tetany 

 following parathyroidectomy, removal of the thyroid will bring about an 

 improvement in his condition. Vassale and Generali were able to cor- 

 roborate this last point in the case of two of their own experimental ani- 

 mals. Le Play later has denied this, and many others corroborate him. To 

 explain their observations on this point, Vassale and Generali put forward 

 the theory that the parathyroids have an antitoxic function, while the 

 thyroid stimulates metabolism. An animal deprived of its parathyroids 

 is a poisoned animal. If the metabolic processes are active, as they will 

 be if the organism possesses a thyroid, this poison will be produced in 

 greater quantity; if less active, as in animals deprived of their thyroids, 

 it will be produced in less quantity. Hence, when an animal is suffering 

 from parathyroidectomy, one might expect an amelioration of the symp- 

 toms after the thyroid is removed. This theory, they argue, is supported 

 by the following facts: Parathyroidectomy is less serious and runs a 

 milder course in old than in young dogs; it is extremely severe in dogs 

 that eat heavily, particularly of meat ; in fasting animals the symptoms are 

 much less severe; in parathyroidectomized dogs the neck wound heals 

 readily by first intention, without any special antiseptic precautions being 

 necessary, whereas, in thyroparathyroidectomized animals it frequently be- 

 comes infected. 



The work of Vassale and Generali was repeated and extended by sev- 

 eral investigators, and about this time a controversy arose, first, as to 

 whether the parathyroid glands are essential to life in all classes of animals, 

 and second, regarding the physiological relationship between the thyroid 

 and parathyroids. 



Investigations as to the Indispensability of the Parathyroids. Blum- 

 reich and Jacoby (1896) concluded that there is no great difference be- 

 tween the effects of thyroidectomy and those of parathyroidectomy. 



Munk (1898) strongly opposed the theory that the parathyroids are 

 'Vitally essential." In a summary of his work up to 1898 it is stated that 

 about fifty per cent of his monkeys and rabbits and twenty-five per cent 

 of his cats and dogs were not affected by the operation. Notwithstanding 

 the assertions of Vassale and Generali, and of others to the contrary, he 



