294 



A MANUAL OF PHYSIOLOGY 



given off by an Animal (Haldane's Method). (i) Connect the 

 apparatus shown in Fig. 133 with the water-pump. Allow a negative 

 pressure of 5 or 6 inches of water to be established in it, as shown 

 by the rise of water in the bell- jar B. Then close the open tube of 

 carbon dioxide bottle i , and clamp the tube between the water-pump 

 and the bell-jar. If the negative pressure is maintained, the arrange- 

 ment is air-tight. Now weigh bottle 3 and bottles 4 and 5 , the last 

 two together. Place a cat in the respiratory chamber A, connect the 

 chamber directly with the water-pump, and test whether it is tight. 

 Then take the stopper out of bottle i, and adjust the rate at which 

 air is drawn through the apparatus. Let the ventilation go on for a 

 few minutes, then insert bottles 3, 4, and 5 again. Note the time 



exactly at this point, and 

 after an hour disconnect 3, 

 4; and 5, and again weigh. 

 The difference of the two 

 weighings of 3 shows the 

 quantity of water given off 

 by the animal in an hour ; 

 the difference in the com- 

 bined weight of 4 and 5 , the 

 quantity of carbon dioxide. 

 Weigh the cat, and calculate 

 the amount of water and of 

 carbon dioxide given off 

 per kilo per hour. 



(2) For the student it is 

 more convenient to use 

 smaller animals. The mouse 

 may be taken as an ex- 

 A, soda-lime tube ; B, sulphuric acid tube ; ample of a warm- blooded 

 C, wooden frame, in which A and B are sup- an i ma l and the frog of a 

 ported by wires d : b, wire hook, which grips co i d _ b iooded. Instead of 

 the glass tube firmly, and by means of which , , Wonlff's bottles use 

 the tubes are lifted out of the frame in order ^ 

 to be weighed ; a. short piece of glass tubing, de test-tubes connected 

 by taking out which the absorption tubes are as . m bl & X 34 ancj 

 disconnected from the rest of the apparatus ; animal chamber a small 

 e, glass tube going off to animal chamber. beaker, closed with a very 



carefully-fitted cork which 



has been boiled in paraffin. The inlet and outlet tubes of the 

 chamber are to be introduced through this cork. The holes for 

 these are to be bored with the greatest care, and the tubes to be 

 put in while the cork is still hot from boiling in paraffin. Also insert 

 a thermometer about 6 inches long registering from o C. to 45 C. 

 Modeller's wax is to be used finally to render all the junctions air-tight. 

 Add to the series of tubes described in the apparatus a single tube 

 containing baryta-water. This is placed to the left of tube 5, and 

 so arranged that the air-current bubbles through the water. As long 

 as the absorption of carbon dioxide is complete, the baryta-water 

 remains clear. Beyond this a water-bottle should be placed to act 

 as a valve and to indicate the negative pressure in the apparatus. 

 It can be most simply constructed by using a cylinder of stout glass 

 tubing in a wide-mouthed bottle containing some water, the inlet and 

 outlet tubes passing through a paraffined cork which seals the upper 

 end of the cylinder. 



Before making an observation, test whether the apparatus is air- 

 tight, as explained above, after introducing the animal into the 



FIG. 134. ABSORPTION TUBES FOR CO., AND 

 MOISTURE. 



