GROWTH AND CHEMICAL PURITY 279 



increased respiration, sweating. She is easily fatigued. 

 Finally, negative proof is found in the fact that if iodin 

 or thyroid extract in small doses be given during preg- 

 nancy, the thyroid will enlarge little if at all. The func- 

 tion of the thyroid is to metabolize iodin, that is, to 

 make iodin available for use in the body economy. 

 Hence, when there is hyperplasia of the thyroid, we 

 assume that the gland is responding to an- increased call 

 for iodin. This evidence shows that the thyroid, like 

 the brain and adrenals, is activated during pregnancy. 



Muscles: Clinical evidence of the participation of 

 the muscles in the activation of pregnancy is found in 

 a distinct loss of muscular power, which may be due 

 to the increased activity of the muscles in maintaining 

 the standard of chemical purity through heat produc- 

 tion. The muscles participate largely in heat produc- 

 tion, and during pregnancy the body temperature is 

 slightly above normal and further increase of tempera- 

 ture is made with abnormal facility. 



Liver: That the work of the liver is increased in 

 pregnancy is shown by urinary findings. If toxemia 

 be present, the decrease in the urea and the increase 

 of ammonia show that the liver is no longer able to 

 perform the entire task of reducing the end products 

 of protein metabolism. In the toxemia of pregnancy the 

 appearance of a high blood-pressure, as in cardiorenal 

 disease, and the increased H-ion concentration of the 

 blood in the stages nearing eclampsia (Michaelis) offer 

 clinical evidence that excessive work is performed by 

 the liver in pregnancy. Further evidence of this fact is 

 seen in the histologic studies of Ewing, which show that 

 massive degeneration of the liver takes place in the 



