ANIMAL HEAT. 515 



The temperature of the mouth is taken by a thermometer grad- 

 uated into tenths. The rectal temperature is preferable because of 

 accuracy. The bucket (/) receives the water from the motor (-3T), 

 and so conveys it to the water-wheel (H) that runs the meter as an 

 aspirator. The meter is filled with water, and belongs to Voit's little 

 respiration apparatus. The quantity of air that is aspirated within an 

 hour is from 5000 to GOOO liters, which is ample for respiratory pur- 

 poses. The instrument is made air-tight by means of the door (K), 

 which is lined at its outer edge with rubber. The whole apparatus is 

 inclosed in over six inches of sawdust, the door (K) having against 

 it a sawdust mattress. 



The door is bound by eight powerful screw-clamps. The air 

 enters the tube (H), then passes through a leaden tube that is coiled 

 upon itself before it reaches the person lying upon the mattress. 



I have tested the calorimeter before and after the performance 

 of my experiments. 



The interior of the instrument is lighted up by an Edison incan- 

 descent light of one-candle power. The patient is thus enabled to 

 spend his time in reading a book while the experimenter is making 

 his observations. 



By placing a pulley outside the calorimeter and attaching to a 

 leather rope a fourteen-pound weight, the man within the instrument 

 is able to exercise. The leather band enters one of the air-holes of 

 the instrument. Of the entire amount of heat dissipated, about 

 14 per cent, is thrown off by the lungs. 



My little calorimeter is constructed upon the same plan as the 

 instrument for men. In this the animal calorimeter the agitator 

 sits astride the inner cylinder, outside of the leaden coils, and is run 

 at the rate of sixty to seventy movements per minute by means of a 

 water-motor. In other instruments the water is occasionally agitated 

 by means of a hand-contrivance. Instead of the air entering the 

 inner chamber by a straight tube, it traverses a tube coiled upon 

 itself in the water reservoir of the instrument to enter the inclosure 

 at its base. The air emerges through the opening at the top to be 

 carried out through the serpentine coil and thence through the 

 aspirating meter. The latter records at the same time the amount 

 of air. The constant activity of the agitator causes the heat to be 

 equally diffused through the water and so permits none to be given 

 to the air. The door swings upon a hinge. In its center there is a 

 through which one can readily see the state of the animal or the 

 >paratus connected with it. At its edge it is lined with rubber and 



