THE NERVOUS MECHANISM OF RESPIRATORY MOVEMENTS 331 



From the percentages obtained in these experiments, and the volume 

 of air breathed per unit of time, computed in Experiment 4 above, deter- 

 mine the amount of carbon dioxide exhaled per hour per kilogram of 

 weight for your own body. Compute also the amount of oxygen con- 

 sumed per kilo per hour; per square meter of surface per hour. 



9. The Rate and Character of the Respiratory Movements in the 

 Mammal. a, The rate of respiration can be best determined by direct 

 count per minute, an effort being made to maintain as nearly normal 



CK 



c d 



FIG. 24.6c. Oxygen and carbon dioxide analyzer, Guthrie form. 

 FIG. 246^. Receiver for air sample, Guthrie form. 



conditions as possible. Make the determinations on a cat, a dog, and 

 a guinea-pig, b, The character of the respiratory movements can be 

 recorded by one of the various forms of stethograph adapted to the size of 

 the animal, or by the arrangement shown in figure 233. It is necessary to 

 make the determination with an animal under the influence of an anes- 

 thetic. 



10. The Nervous Mechanism of Respiratory Movements. a. The 

 Ejffett of Stimulating Cutaneous Nerves. Use a small dog or a cat for 

 this experiment; anesthetize and introduce a tracheal tube with a side 



