THE KINETIC SYSTEM 



191 



the body is correspondingly diminished. This diminu- 

 tion of energy is evidenced in muscular and mental 

 weakness, and in diminished response to all types of 

 stimuli. 



B. 



C. 



Section of normal cere- 

 bellum of dog. 



Section of cerebellum Section of cerebellum 

 of dog after adrenalec- of dog after repeated in- 

 tomy. jections of adrenin. 



FIG. 41. COMPARATIVE EFFECTS OF EXCISION OF THE ADRENALS AND OF 

 EXCESSIVE ADMINISTRATION OF ADRENIN ON THE BRAIN-CELLS OF 

 DOGS. 



The disastrous effect of withdrawing adrenin from the kinetic system is 

 apparent in B in the extensive loss of chromatic material in all the cells, 

 the disintegration of many and the almost complete degeneration of some 

 cells. The effect of a continuous activation of the system by the excessive 

 administration of adrenin is strikingly shown in C by the large number of 

 hyperchromatic cells, together with evidences of exhaustion and disintegra- 

 tion in some cells. These effects are similar in kind and analogous to the 

 effects produced by withdrawing thyroid secretion or by administering 

 excessive doses of thyroid extract. 



(From photomicrographs, X 310.) 



Muscles: It has been observed clinically that if the 

 muscles are impaired by long disuse or by a disease such 

 as myasthenia gravis, the range of production of both 

 heat and motion is below normal. This is in agree- 



