1911.] Ventilation of the Lung during Chloroform Narcosis. 369 



the cases of death at this stage which we have investigated, the- heart 

 continued to beat for some little time after respiration ceased. 

 • In order to throw light on this question, we made analyses of the blood 

 gases of cats under urethane, in which, as the plethysmograph showed, the 

 respiration was extremely regular and constant and the lung ventilation 

 medium in amount. The results are given in Table XIV, and compared with 

 the average of four analyses of the blood of un anaesthetised cats which 

 exhibited marked hyperpncea, taken from our former paper.* 



Table XIV. 





Composition of the blood gases of cats 

 under urethane in c.e. per 100 c.c. 

 of blood. 



Remarks. 



Alveolar 

 Composition 



air 



of lung 



Total gas. 



CO.. 



O. 



, 



C0 2 . 



0. 



N. 



1 



60-70 



49 -43 



10 -01 



1 -21 



10 c.c. of blood 









2 





42 -03 



12-56 



0-95 



Same cat as 1, 1 hour 



























3 



51 -17 



38 "68 



17 -43 



1-07 



Shallow panting respi- 



5 -74 



9-66 



84-59 













ration 









4 



60 -70 I 



49-48 



10-01 



1 -21 













55 -54 



42 -03 



12-56 



0-95 



Same cat as 4, 1 hour 



























6 



50 -01 



31 -77 



16 -68 



1-55 











7 



64 -71 



47 -84 



15 -66 



1 -22 



Respiration slow and 



6-24 



9-15 



84-69 





















8 



51 -57 



35-76 



14 -89 



0-91 





4-93 







9 



51-17 



38 -03 



12-03 



1 -07 





6-25 



9-74 



84 -02 





Average of four analyses of the blood of 













unaniesthetised* eats in whic 



hthe 













respiration 



was rapid and deep 



and the 













lung-ven 



tilation a 



jnorrnally great. 













35 -03 j 



20 -56 



13 -49 



0-96 











* ' Journ. Physiol.,' October 11, 1910, vol. 41, p. 62. 



The comparison of these analyses clearly shows that with a deep and rapid 

 respiration the carbon dioxide content of the blood is much less than when 

 the lung-ventilation is normal in character. 



Since the dead-space in respiration is constant, it is evident that, with 

 reduced ventilation, a proportionately less amount of inspired air is intro- 

 duced for diffusion with alveolar air, and consequently the carbon dioxide and 

 nitrogen should accumulate in the alveolar air, and the oxygen content should 

 dimmish. These variations, however, could not be very great ; at any rate 



* Mourn. Physiol.,' Oct. 11, 1910, vol. 41, Nos. 1 and 2, p. 62, Expts. I, II, III, 

 and IV. 



