322 Biology in America 



tial energy is converted into active or kinetic energy, and the 

 tissues of the body suffer corresponding loss. According 

 to Crile certain parts of the brain furnish the nervous en- 

 ergy, which is probably identical with electrical energy, and 

 which controls muscular, and other activity. The adrenal 

 glands furnish adrenalin, which in some way determines the 

 oxidation processes in the brain to which the nervous energy 

 is due. The thyroid gland, which Crile calls the ''pace- 

 maker" of the body, furnishes iodin to the tissues and ren- 



EFFECT OF THE KINETIC DRIVE 



Photograph of a soldier under extreme mental and physical stress. 

 From Crile, "The Kinetic Drive." "Journal of the American Medical 

 Association," Vol. LXV. 



ders them more permeable to the nervous impulses. In the 

 conversion of energy in the body certain acid waste products 

 are formed which are eliminated by the liver, kidneys and 

 lungs. The blood is thus kept alkaline, in which condition 

 only is the carriage of oxygen to the tissues possible. 



If the production of adrenalin, the secretion of the ad- 

 renal glands, be prevented, either by removal of these glands, 

 by cutting the nerves which supply them or by narcotizing 

 the latter with morphin, activity is reduced. On the other 

 hand administration of adrenalin produces results similar to 



