RESPIRATION. 



351 



and the respiratory action is revealed only by the movements of the 

 abdominal wall; this becomes projecting during inspiration and 

 sinks during expiration. In the inferior costal type, man's type, the 

 respiratory movements take place especially at the level of the lower 

 ribs, beginning with the seventh. Finally, in the superior costal, or 

 clavicular, type, the respiratory movements are very manifest only 

 about the upper ribs, especially the first, which are carried upward 

 and forward. The clavicle also participates in this movement. This 

 last type is the mode of respiration peculiar to women, who pre- 

 sent it very early. The state of pregnancy, which would greatly 

 interfere with the other types of respiration, does not hinder breath- 

 ing very much in this last type, since the movements take place 

 naturally at the upper part of the chest. 



Fig. 121. Tracing of a Respiratory Movement. ( FOSTER.) 



A whole respiratory movement is comprised between a and a, inspiration 

 extending from a to & and expiration from & to a. The waves at c are caused 

 by heart-beats. 



Mays and Kellogg have found that pure-blooded Indian girls, 

 who have never worn corsets, usually have the abdominal type and not 

 the costal type of respiration. Fitz found little or no difference in the 

 type of respiration of the two sexes when the corset had been removed. 



The superior costal type is perfectly established in girls and 

 women who have never worn a corset and this is probably due to 

 heredity. 



Among animals the abdominal type of respiration is found in 

 the horse, the cat, the rabbit and the inferior costal type in the dog. 



The Stethograph, or Pneumograph. To gain an exact idea of 

 the time occupied in the various phases of respiration it becomes neces- 

 sary to obtain its curve, or pneumatogram. The apparatus for re- 

 cording these respiratory movements is termed a stethograph, or 

 pneumograph. 



The simplest form of stethograph is that of Brondgeest. It con- 

 sists of a brass saucer-shaped vessel covered with a double layer of 





