394 REGULATION OF THE TEMPERATURE. 



hours. Direct transfusion from an artery to an adjacent vein in the 

 same animal excites the same phenomenon. 



Certain poisons, particularly chloroform, chloral and other anes- 

 thetics, as well as alcohol; further, digitalis, quinin and others, cause 

 reduction in temperature. These substances appear in part to render 

 the tissues less suited for the molecular decomposition necessary for the 

 generation of heat. In the case of the anesthetics it is possibly a con- 

 dition of the latter kind within the structure of the nerve that furnishes 

 the cause. In part, however, they may also have an influence upon 

 those processes that control the dissipation of heat from the body. 

 Other poisons cause elevation of temperature from opposite causes. 



Strychnin, nicotin, picrotoxin, veratrin, laudanin, cause elevation of the 

 bodily temperature. The lowest temperature terminating in recovery observed 

 was 24 (!) C.jn the rectum of a profoundly intoxicated individual. 



Reduction in temperature in connection with disease is due either 

 to diminished heat-production (reduction in metabolic activity), or to 

 increased heat-dissipation. 



Marked reduction in temperature in individual instances (between 31 and 

 27.5 and down to 22 C. in the anus) has been observed particularly in cases of 

 paralysis, in one of which Reinhard found a rectal temperature of as low as 

 22.5 C. four and one-half hours before death. The lowest temperature observed 

 one day before death was 23 C. in the anus in a case of hemorrhage into the 

 medulla oblongata. Also in cases of diabetes a reduction in temperature below 

 30 C. has been observed. 



Elevation of temperature is exhibited as a rule in connection with 

 fever, the highest temperature being observed by Wunderlich before 

 death, 44.65 C. 



REGULATION OF THE TEMPERATURE. 



As human beings and other homoiothermic animals are capable of 

 maintaining their bodily temperature at the same level under varying 

 conditions, the body must possess special mechanisms by means of which 

 the heat-economy is subjected to constant regulation. The latter can 

 obviously make itself effective in two directions : either by control of the 

 amount of molecular transformation through which potential energy is 

 transformed into the kinetic energy of heat, or by influencing the dissi- 

 pation of heat from the body in accordance with the production or the 

 effects of external agencies. 



Regulatory Mechanisms Governing He at- production. 



C. v. Liebermeister estimated the heat-production of a medium- 

 sized person as 1800 calories per minute. It is in the highest degree 

 probable that mechanisms are operative in the body upon whose stimula- 

 tion the amount of heat-producing molecular transformation is depen- 

 dent. It should especially be borne in mind that this stimulation is of 

 reflex origin. Irritation from the peripheral extremities of the cutane- 

 ous nerves, through thermic excitation, or of the nerves of the intes- 

 tines and of the digestive glands, through mechanical or chemical 

 stimulation during the process of digestion or during inanition, may 

 be transmitted to a heat-center, from which an influence is exerted 

 through centrifugal fibers upon the reservoir for potential energy, for the 

 purpose of stimulating either increased or diminished metabolism. Little 

 is as yet known, however, concerning the nervous apparatus and chan- 



