IT 



THE EFFECTS OM RESPIRATION OF CHANGES IN 

 THE 4TR BREATHED 



Wml 



tfeair 

 tfcee&x*. If the amount of 



to tfe spasm of the glottis prodoced by the 

 H tfae high percentages be ad- 

 by a tzaeheal tube, violent dyspuea is produced 



>'-' ' :.. ; - .---- -.' . "J *:.-- ;;" _*--:. >- 

 d oat even in the prfarnfae of excess of 

 of larger pereedUges, such as 30 or 40 per 

 d faitae of tie circulation and respiration, often 

 Coincident with the increased respiration brought 

 about by moderate percentages of carbon dioxide, there is a rise of blood 

 pmiuge determined by vascular constriction. With high percentages of 

 carbon dioxide the curve of blood pressure obtained resembles that produced 

 by lack of oxygen. 



Oxygen itself exercises no excitatory effects on the respiratory n 

 ment*. At the normal atmospheric pressure the tension of oxygen in the 

 alveoli i about 107 mm. Hg., a pressure which, as we have seen, is amply 

 sufficient to saturate the h^nno^obm passing through the vessels of the 

 lungs, Since the depth and frequency of respiration are determined by the 

 carbon dioxide tension in the alveoli, no alt < . , respiration will be 



produced by increasing the tension of oxygen in the air breathed above its 

 normal amount. The respiratory movements in an atmosphere of pure 

 normal individual, remain 1 



This statement if true only for the healt h . individual. Tf from failure of the heart 



:IM| Mr- ' -,n from rjirnini l."l o>. . ;"'r, t. n-iou, f,r f rr,,,, <-<-vr<- Jo-,- of blood, thf^ OXy- 



JI1H 



