RESPIRATOR Y CHANGES IN AIR. 



697 



the respiratory exchange in animals. It has the advantages and most 

 of the disadvantages above mentioned. The human respiration apparatus 

 in the physiological laboratory, Oxford, has been constructed on the 



PUMICE & 

 H2 504 



FIG. 64. Diagram of the human respiration apparatus in the Physiological Laboratory 

 Oxford. A. To Aspirator. 



principle of Pettenkofer's apparatus, but has been made more exact and 

 simple by the use of Haldane and Pembrey's method of determining 

 carbon dioxide and moisture. 



A more exact method is that introduced by Haldane. 1 It is a 



FIG. 65. Haldane's respiration apparatus. 1 and 4, soda lime ; 2, 3, and 5, pumice 

 soaked in sulphuric acid ; Ch, chamber for animal ; M, gasmeter ; J, water mano- 

 meter ; P, aspirator. 



modification of the apparatus used by Scharling and Pettenkofer, but 

 the chief sources of error have been eliminated or greatly diminished, 

 and the method has been made extremely simple. The construction is 

 shown in Fig. 65 : 



1 Journ. Physiol., Cambridge and London, 1892, vol. xiii. p. 419. 



