FREQUENCY OF RESPIRATORY MOVEMENTS. 391 



wise follow the physiological enlargement of the uterus. In 

 pathology it is observed that, in consequence of this peculiar- 

 ity, females are able to carry, without great inconvenience, 

 immense quantities of water in the abdominal cavity ; while 

 a much smaller quantity, in the male, produces great distress 1 

 from difficulty of breathing. 1 



Frequency of the Respiratory Movements. In counting 

 the respiratory acts, it is desirable that the subject be uncon- 

 scious of the observation, otherwise their normal character is 

 apt to be disturbed. Of all who have written on this sub- 

 ject, Hutchirison presents the most numerous and convincing 

 collection of facts. This observer ascertained the number of 

 respiratory acts per minute, in the sitting posture, in 1,897 

 males. The results of his observations, with reference to fre- 

 quency, are given in the following table : 2 



Bespirations per minute. Number of cases. 

 From 9 to 16 79 



16 239 



17 105 



18 195 



19 i 74 



20 561 



21 129 



22 143 



23 42 



24 ..^. 243 



24 to 40 87 



Though this table shows considerable variation in differ- 

 ent individuals, the great majority (1,731) breathed from six- 

 teen to twenty-four times per minute. Nearly a third 

 breathed twenty times per minute, a number which may be 

 taken as the average. 



1 Modifications of the types of respiration by disease are frequently very 

 marked. In peritonitis, when movements of the diaphragm would be productive 

 of excessive pain, the abdominal type may be wholly suppressed. In the early 

 stages of acute pleurisy, the affected side may become nearly or quite motionless. 



1J Cyclopaedia of Anatomy and Physiology, vol. iv., part ii., p. 1085. 



