80 



COMPARISONS OF RESPIRATORY EXCHANGE. 



In use the hand spirometer is attached to the tee piece between a 

 pair of valves or connected with the three-way valve of the unit respira- 

 tion apparatus; then, by raising or lowering the bell, the valves may be 

 opened or closed as in ordinary respiration or the tension equalizer or 

 the spirometer of the unit respiration apparatus may be made to rise 

 and fall. By the use of this apparatus it is possible to simulate respira- 

 tion closely so far as volume and time are concerned. With the bath 

 filled with water the spirometer is also used for the efficiency tests on 

 the unit-respiration apparatus and for the calibration of the ventilation 

 adder. 1 In some experiments with a pair of valves carbon dioxide has 

 been introduced between the valves at such a rate as would simulate the 

 production of this gas by man. The apparatus has proved extremely 

 useful in testing respiration apparatus. 



APPARATUS FOR ALCOHOL CHECK-TESTS OF THE 

 TISSOT METHOD. 



To test the accuracy of the Tissot method 2 

 for the measurement of the respiratory exchange, 

 an apparatus was devised for making experi- 

 ments with burning alcohol. The general 

 arrangement is shown in figure 34. A burette, 

 A, divided into 0.01 c.c. and with a capacity of 

 a little over 5 c.c, was connected to a lamp, B, 

 by means of rubber tubing and capillary copper 

 tubing. A screw pinchcock, 0, on the rubber 

 tubing, controlled the flow of alcohol from the 

 burette. The lamp was a brass cup with an 

 opening about 0.5 cm. diameter and was inclosed 

 in a glass chamber, D, made of the outside part 

 of a Zuntz valve (see fig. 19, page 54). The 

 upper end of this chamber was connected by 

 a tee piece, E, to the hand spirometer, M N, 

 and by a second tee piece, G, to a Tissot valve, 

 J. The open end in the tee piece, G, was 

 closed by a rubber stopper, K. The lower end 

 of the chamber, D, was connected with a second 

 Tissot valve by a tee piece, F, the open end of 

 which was closed by a rubber stopper, L. The 

 whole apparatus was mounted by means of 

 clamps and rings upon a large ring stand. 



A test with this apparatus was carried out as 

 follows: The burette A was filled with alcohol, 

 which was allowed to pass out through the tubing and lamp, and 

 when they were free from air-bubbles the screw pinchcock was 



Fig. 34. — Apparatus used 



for alcohol check-tests 



of the Tissot method. 



A, burette; B, alcohol 



lamp; D, glass chamber; E, 



F, and G, brass tee pieces; 



H and J, Tissot valves; K 



and L, rubber stoppers; M, 



N, hand spirometer; O, 



pinchcock. 



»See p. 43. 



2 See description on p. 61. 



