BIOLOGY IN HUMAN AFFAIRS 



crude form, to be sure — the use of this hormone to bring 

 about complete and lasting relief from the symptoms of 

 removal of the glands, and the demonstration that the 

 activity of the hormone is proportional to its calcium- 

 mobilizing effect. After removal of these glands in dogs, all 

 abnormal symptoms can be suppressed and life prolonged 

 indefinitely by repeated injection of the extract containing 

 the hormone. The effect is as remarkable as that of insulin 

 in diabetes. The calcium content of the blood of a normal 

 unoperated dog is also increased by injection of the hor- 

 mone, v^hich is similar to the action of insulin in decreasing 

 the blood sugar of a normal non-diabetic animal. This 

 action on the calcium of the normal has been utilized for 

 the biological standardization of the parathyroid hormone. 



Concerning the chemical nature of this parathyroid 

 hormone, very little is know^n as yet. No doubt, success 

 will come in the future in the isolation of the active 

 principle as a pure chemical individual, as has already 

 happened for insulin and the hormones of the adrenal 

 medulla and the thyroid and the ovary. This will be a 

 great step forward, and will undoubtedly aid in solving 

 the fascinating problem as to how this hormone acts to 

 regulate the calcium content of the blood. The final 

 step in our knowledge of the hormone will be a determina- 

 tion of its chemical constitution and a synthesis in the 

 laboratory. We cannot do more than mention here that 

 this parathyroid hormone has already been used successfully 

 in the treatment of various conditions of tetany in children, 

 due, presumably, to an underfunctioning of the parathyroid 

 glands. It is possible that the hormone may be of service 

 in many conditions where the metabolism of calcium is 

 disturbed. 



In conclusion, it is important to recognize the tremendous 

 amount of laborious work which must be done before even 

 small minor points in regard to the functioning of the 



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