RESPIRATION 123 



emptying take a specimen of out-of-door air and determine its oxygen, 

 taking care to let it reach room temperature before measuring it. 



After the second change of the ventilating apparatus take 100 c.c. 

 of air from every 8 or 10 litres of air that traverse the cage and 

 determine the oxygen. Note very carefully the amount of air that 

 traverses the animal cage and keep the ventilating stream as regular 

 as possible. 



At the end of the experiment take a second 100 c.c. of air from 

 out of doors and determine its oxygen. 



4. Observations. (1) How many cubic centimetres of oxygen 

 has the animal consumed during the experiment, measured at the 

 room temperature and the pressure read from the barometer? 



(2) Reduce the volume of oxygen, as determined under the con- 

 ditions given above, to the volume which it would represent if meas- 

 ured under standard conditions of C. and 760 mm. pressure. 



(3) How many milligrams of CO 2 were caught by the Geissler bulb ? 



(4) How many cubic centimetres of CO 2 at C. and 760 mm. 

 barometric pressure would be equal to number of milligrams deter- 

 mined under (3). 



.(5) What is the respiratory quotient? R. Q. = ^ --*= 



vol. ^'2 



(6) Is the subject of the experiment a carnivorous, omnivorous, 

 or herbivorous animal? 



(7) What has been the diet of the animal during the last three 

 days before the experiment? 



(8) How long before the experiment had the animal eaten? 



(9) Determine the influence of diet on respiratory quotient. 



(10) Determine the influence of fasting on respiratory quotient. 



IX. RESPIRATION UNDER ABNORMAL CONDITIONS. 



1. Appliances. Six small animals e.g., rats or guinea-pigs; six 

 wide-mouthed bottles or jars, which may be sealed; scales or large 

 balances; CO 2 generator; water-bath; operating case; dissecting 

 boards. 



2. Preparation. Determine the weight of animals "'a," "b," and 

 "c." Choose a receptacle whose cubic contents is not over twice 

 as many cubic centimetres as the weight of animal "a" in grams. 

 Choose second and third receptacles whose contents represent about 

 10 c.c. to 1 grm. of animals "b" and "c," respectively. 



3. Operation. I. Preliminary, (a) Put animal "a" into the small 

 jar "a;" count respirations; close the jar. 



(b) Put animal " b " into jar" b." Before closing count respirations; 

 close air-tight. 



(c) Fill jar "c" one-third full of water and displace the water with 



