THE THYROID AND PARATHYROID GLANDS 761 



toms like those of tetany can be induced by deficiency of calcium in the 

 body and the symptoms of parathyroidectomy relieved by administration 

 of this cation, calcium deficiency is the cause of the symptoms. While 

 not denying that these ions may have some relationship to the symptoms, 

 Noel Paton ascribes tliem to intoxication by yiianidine (page 605). The 

 evidence is as follows: (1) Guanidine and methyl guanidine admin- 

 istered to normal animals produce symptoms that are identical with those 

 following parathyroidectomy. (2) There is a marked increase in the 

 amount of these substances in the blood and urine of parathyroidec- 

 tomized dogs and in the urine of children suffering from idiopathic 

 tetany. (3) In certain cases the serum of parathyroidectomized dogs 

 acts upon the muscles of the frog similarly to weak solutions of guani- 

 dine and methyl guanidine. (4) There is a striking similarity in the 

 relative amounts of the nitrogenous metabolites in the urine of parathy- 

 roidectomized dogs and of normal animals injected with guanidine. 



It is concluded that the parathyroids control the metabolism of guani- 

 dine "by preventing its development in undue amounts. In this way 

 they probably exercise a regulative action upon the tone of the skeletal 

 muscles." Since it is similar with regard to its characters and metabo- 

 lism to the condition following thyroidectomy, it is believed that disease 

 of the parathyroids is the cause of idiopathic tetany. 



The Relationship of the Parathyroid with Other Endocrine 



Organs 



We know very little of the relationship of the parathyroid with other 

 endocrine organs. Vincent and others have stated that after removal 

 of the thyroid itself enlargement of the parathyroid may occur with the 

 formation of colloid material between the rows of cells, but the con- 

 clusion that this represents a vicarious function between the thyroid and 

 parathyroid glands is not generally accepted. The supposed relation- 

 ships among the parathyroid and the pituitary and adrenal glands are 

 also based upon uncertain evidence. 



