214 A MANUAL OF PHYSIOLOGY 



movements of the diaphragm predominate, the respiration is 

 said to be of the abdominal or diaphragmatic type ; when the 

 movements of the upper ribs and sternum are most conspicuous, 

 of the costal or thoracic type. In abdominal respiration, the 

 inspiratory movement commences at the diaphragm, and then 

 involves the lower ribs and the tip of the sternum. In costal 

 respiration, the upper ribs initiate the movement, and are 

 followed by the abdomen. In the rabbit, during quiet breathing, 

 the respiration is purely diaphragmatic, the ribs remain motion- 

 less ; and herbivorous animals in general conform more or less 

 closely to this type. In the carnivora, on the contrary, the 

 costal type prevails. Man allies himself as regards his respira- 

 tion with the rabbit and the sheep ; he uses his diaphragm more 

 than his upper ribs. Civilized woman falls into the class of the wolf 

 and the tiger ; she uses her upper ribs more than her diaphragm. 

 The cause of the difference between men and women has been 

 much discussed. It is not a primitive sexual difference, for it is 

 far from being universal ; in the uncivilized and semi-civilized 

 races that have been investigated, the women breathe like the 

 men. It is therefore probable that the predominance of the costal 

 type among women of European race is a peculiarity developed 

 by a mode of dressing which hampers the movements of the 

 diaphragm while permitting the elevation of the ribs. This con- 

 clusion is strengthened by the fact that in children no difference 

 exists ; both boys and girls show the abdominal type of respiration. 



All this refers to ordinary breathing. In forced respiration, 

 when the need for air becomes urgent, costal breathing always 

 becomes prominent alike in men, in women, and in animals, for 

 by elevation of the ribs the capacity of the chest can be increased 

 to a greater degree than by any contraction of the diaphragm. 



In forced inspiration, indeed, all the muscles that can elevate 

 the ribs may be thrown into contraction, as well as other muscles 

 which give these fixed points to act from. During a paroxysm 

 of asthma, for example, the patient may grasp the back of a 

 chair with his hands, so as to fix the arms and shoulders and 

 allow the pectorals and serratus magnus to raise the ribs. Simi- 

 larly in forced expiration all the muscles are used which can 

 depress the ribs, or increase the intra-abdominal pressure and 

 push up the diaphragm. 



Artificial Respiration. An efficient pulmonary ventilation can 

 be obtained by various methods when the natural breathing is in 

 abeyance. In animals the method most commonly employed 

 for experimental purposes is the rhythmical inflation of the lungs 

 by a pump or bellows, or by a stream of compressed air which is 

 regularly interrupted, the chest being allowed to collapse after 

 each inflation. When the animal is to be kept alive after the 



