34 SECRETION 



moval is followed by weakness, impaired nutrition and dis- 

 turbances in the circulation. Death usually supervenes in 

 two to four days. These bodies must produce an internal 

 secretion which is removed by way of ,the adrenal veins. It 

 may destroy toxic substances in the blood. A solution in- 

 jected into the circulation certainly affects the middle wall 

 of the vessels, causing contraction, and a heightened pres- 

 sure. The heart is also notably inhibited. It is not thought 

 that the effect on the vessels is brought about through the 

 vaso-motor nerves, but by direct excitation of the muscular 

 substance. Little in fact is known about the secretion, ex- 

 cept that it is necessary to life. Abel has isolated an alkaloid, 

 epinephrine, which is claimed to be the active principle. 

 These glands are the seat of lesions in Addison's disease, and 

 many cases of this malady are at least favorably influenced 

 by the use of adrenal extract. 



Pituitary Body. 



The pituitary body lying in the sella turcica on the superior 

 surface of the sphenoid bone, also produces an internal se- 

 cretion of physiological value. Its removal is regarded as 

 causing death. Hbwell has shown that injection of extract 

 from the posterior division occasions a rise of temperature 

 and slowing of the heart. Its situation makes satisfactory 

 experiments very difficult. 



Testis and Ovary. 



The testes and ovaries, though not probably true glands, 

 also may produce an internal secretion of obscure physio- 

 logical value. It is not essential to life. Injections of ex- 

 tracts from these bodies are claimed to have a remarkable 

 stimulating effect upon the nervous and muscular systems. 

 In mental and physical disturbances occasionally following 

 removal of the ovaries, gynecologists often find administra- 

 tion of the ovarian extract to be beneficial. 



