RESPIRATION H9 



test joints place the finger over the distal tube of the Woulffe bottle 

 (a); if the joints are all right the siphon stream will stop after a 

 few moments. When the water in the upper bottle is lowered nearly 

 to the end of the siphon, clamp the tube joining h to i, set the empty 

 bottle upon the floor and the full bottle on the higher level, join the 

 tube at k, and unclamp. This whole change need only occupy a 

 few seconds. If it is desired to make a determination of the amount 

 of oxygen which the animal consumes in a given time, the air that 

 passes out of the ventilating apparatus after the second change may 

 be caught and tested. 



(4) It is evident that in the afferent apparatus (a, 6, and c) one 

 has a means of robbing the air of CO 2 and H 2 O, thus furnishing the 

 animal with pure dry air. It is further evident that in the (afferent - 

 apparatus one has a means of collecting absolutely all of the CO 2 

 and H 2 O given off from the animal during the experiment. Further, 

 the weights before and after will show just how much of these excreta 

 have been passed into the collecting apparatus. 



(5) Note the time (one hour or more); clamp siphon tube; turn 

 the stoppers off e and /, clamp x and y; disjoin d and weigh it. 



(6) Weigh e, weigh /, weigh g. 



4. Observations. (1) How much has the animal lost in weight 

 during the period of observation? 



(2) How much water left the animal cage during the period of 

 observation ? 



(3) What was the source of this water? 



(4) Did the animal micturate or defecate during the time of the 

 experiment? If so, is this to be looked upon as a source of error in 

 the experiment? Would such an occurrence tend to increase or 

 decrease the amount of water caught in the CaCl 2 tubes e and ff 

 Would it interfere in any way with the experiment? If so, how 

 may such a source of error be avoided or corrected? 



(5) How much CO 2 left the animal cage during observation? 



(6) What is the total amount of CO 2 and H 2 O collected? 



(7) Does the amount of these excreta collected equal the loss in 

 weight of the animal ? What should the relation of these two quanti- 

 ties be? Explain in full. 



(8) What is the respiratory quotient? 



(9) Formulate several problems which may be solved with this 

 method. - 4 



VII. TO DETERMINE THE AMOUNT OF OXYGEN CONSUMED 

 BY AN ANIMAL IN A GIVEN TIME. 



1. Preparation. The oxygen is determined by a volumetric 

 method, using two or more gas burettes and a solution of potassium 

 pyrogallate. 



