SECRETION OF TEE DUCTLESS GLANDS. 877 



prevails that complete removal of the parathyroids is followed by 

 acutely toxic results which develop rapidly, and the most common 

 symptom of which is muscular tetany. This tetany exhibits 

 itself as fibrillar contractions of the muscles, a general muscular 

 tremor, tonic and clonic spasms of the muscles or " intention 

 spasms," that is, spasmodic or uncoordinated contractions follow- 

 ing upon an effort to make a voluntary movement * As is well 

 known, similar symptoms are often observed under other condi- 

 tions, infantile tetany, gastro-intestinal tetany, etc., and it has 

 been suggested that in all such cases the initial difficulty may 

 consist in the insufficiency of active parathyroid tissue. Several 

 observers have reported that injections of extract of the parathy- 

 roids cause the tetany to disappear without, however, protecting 

 the animal from a fatal outcome. Macallum and Voegtlinf 

 find that injection or ingestion of solutions of calcium salts removes 

 completely the symptoms of tetany and restores the animal to 

 an apparently normal condition. They have obtained similar 

 results upon human beings suffering from tetany as a result of 

 unintentional removal of the parathyroids. The experimental 

 evidence in the case of the parathyroids tends to support the 

 view that their function consists in neutralizing in some way 

 toxic substances formed elsewhere in the body, and that, therefore, 

 after removal of these glands death occurs from the accumulation 

 of such toxic bodies in the blood and tissues. Thus Macallum 

 states that in animals in which tetany has developed as a conse- 

 quence of extirpation of the parathyroids, bleeding and infusion 

 of salt solution causes the tetany to disappear, a result which may 

 be explained by supposing that some toxic substance has been 

 removed. One specific hypothesis along this line has been suggested 

 by Patont and his co-workers. They found that the symptoms 

 observed after extirpation of the parathyroids may be produced 

 also by injections of salts of guanidin, and since after parathyroid- 

 ectomy there is a marked increase of guanidin compounds in the 

 blood and urine they come to the conclusion that the parathyroids 

 are concerned in the regulation of the metabolism of the guanidin 

 compounds in the body. When these bodies are removed the 

 guanidin accumulates in the blood and gives rise to the tetany 

 and fatal result. The view that the parathyroids are simply im- 

 mature thyroid tissue is still supported by some observers, being 

 based chiefly on the histological finding that after removal of the 

 thyroids the parathyroids may hypertrophy and show thyroid 



* For literature and summary, see Bing, "Zentralblatt f. d. Physiol. u. 

 Pathol. d. Stoffwechsels," 1908, Nos. 1 and 2; also Biedl, loc. cit. 



f Macallum and Voegtlin, "Johns Hopkins Hospital Bulletin," March. 

 1908. 



t Paton, et. al, "Quarterly Journal of Exp. Physiology," 1917, 10, 203. 



