XXXII. Respiration under abnormal conditions. 



1. Appliances. Three small animals, e. g., mice, rats, 

 guinea pigs or squirrels. Three 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 each animal. 

 Choose a receptacle whose cubic contents is about two to 

 three times as many cubic centimentersas the weight of 

 animal "a" in grams. Choose second and third recep- 

 tacles whose contents represent about 12 to 15 c. c. to 

 one gram of animals "b" and "c," respectively. 



j. Operation. 



I. Preliminary. 



a. Put animal "a" into the small jar "a"; count res- 

 pirations; 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 CO 2 . Put animal "c" into the jar, tak- 

 ing care to allow as little loss of CO 2 as possible; 

 close; count respirations. 



II. Post-mortem examination. 



After an animal dies fix it to the dissecting board and 



open the abdominal and thoracic cavities; take great 



care not to cut a large blood vessel; pin the flaps out 



so that all of the organs will be exposed and in place. 



4. Observations. 



a. Respiration in small closed space. 



(1) Make careful record of number of respirations 



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