EESEAECHES UPON FEVER. 421 



When the spinal cord of an animal is cut above the origin of the 

 splanchnic nerves there is usually a great fall of the bodily temperature, 

 which is in a measure proportionate to the temperature of the surround- 

 ing air. If the animal be placed in a heated apartment the fall of ten*- 

 perature is greatly lessened, and is sooner or later followed by a rise. 

 In some animals the rise of temperature thus brought about is even 

 greater than occurs in a normal animal placed in a similarly heated 

 room. When the animal with a divided cord is in a cold room, death 

 evidently is the result of the cold, the bodily temperature continually 

 falling more and more until a point fatal to life is reached. The animal 

 with a divided cord will live almost indefinitely in a room heated to 

 80°, but perishes in a very short time in a room of 40°. Another series 

 of phenomena connected with spinal division is that where the cord is 

 divided at its junction with the pons there is a very rapid rise of the 

 bodily temperature, even in a cold room, to a point far above normal. 

 It is plain that these phenomena may be either due to disturbances of 

 heat evolution or of heat production, and that before any explanation of 

 them can be satisfactorily given this point should be settled. This has 

 been done by means of a calorimeter, whose general plan of construction 

 resembles that of Senator. The principle of this is the heating of a given 

 weight of water in a given time. This calorimeter measures only the 

 amount of heat given off by the animal, or, in other words, heat evolu- 

 tion. K the animal gain in his bodily temperature during his stay in the 

 calorimeter, it is plain that heat evolution is less than the heat produc- 

 tion, and vice versa. 



By taking the specific heat of the animal as the proportional mean 

 of the specific heat of its constituents, namely as .75, we are able to 

 calculate in heat units the amount of caloric lost or gained by the body, 

 and to add to or subtract from the heat evolved as may be required to 

 determine the amount of heat produced. 



Employing this method it was found that immediately after section of 

 the cord there is great increase of the heat evolution, if the calorimeter 

 be at an ordinary temperature. On the other hand, when the hourly 

 heat evolution was measured, some hours after the section, it was fouuil 

 to be much less than before the operation. The first increase of the 

 heat evolution was always associated with a great fall of bodily tem- 

 perature ; and when the calculations were completed it was found that 

 the extra heat imparted to the calorimeter during the first hour after 

 ,the spinal section was not equal to the amount lost by the body, or, in 

 other words, that immediately after the operation there was lesseneil 

 heat production. In the subsequent hours of hfe, both heat production 

 and evolution are markedly lessened. The result thus obtained may \)e 

 stated as follows : Section of the cord at usual temperatures is followeil 

 by markedly lessened production of animal heat, continuing until death, 

 and also by an immediate excessive loss of heat, which continues until 



