xxii CONTENTS. 



293. The complex nature of the medullary respiratory centre ; the sub- 

 sidiary spinal mechanisms 473 



294. The action of the centre automatic 474 



295. The centre influenced by afferent impulses. The respiratory action 



of the vagus nerve. Inhibitory and augmentor effects . . 475 



296. The double action of the centre, inspiratory and expiratory. Antag- 

 onism between the two 479 



297. The effects of inflation and suction. Double action of the vagus 



fibres. Self-regulating mechanism 480 



298. The influence on the respiratory centre of various afferent impulses 483 



299. The respiratory centre composed of two lateral halves . . . 484 



300. The respiratory centre influenced by the condition of the blood 



brought to it. Eupnoaa, hyperpnoaa, and dyspnoea . . . 484 



301. The direct character of these influences. Effects of heat on the 



respiratory centre 486 



302. The relative shares taken by deficiency of oxygen and excess of 



carbonic acid in the above influences 487 



303. Changes in the blood other than differences in the gases influence 



the respiratory effect. The effects of muscular exercise . . 488 



304. The phenomena and causes of apncea 489 



305. Secondary respiratory rhythm. The Cheyne- Stokes respiration . 490 



SECTION VII. 

 THE EFFECTS OF CHANGES IN THE COMPOSITION AND PRESSURE 



OF THE AlR BREATHED. 



306. The phenomena of asphyxia 491 



307. The effects on respiration of breathing various foreign gases . . 494 



308. The effects of a diminution of pressure in the air breathed . . 494 



309. The effects of an increase of atmospheric pressure .... 496 



SECTION VIII. 

 THE RELATIONS OF THE RESPIRATORY SYSTEM TO THE VASCULAR 



AND OTHER SYSTEMS. 



310. The respiratory movements influence the circulation. The respira- 

 tory undulations of the blood-pressure curve .... 497 



311. The effects of the expansion of the thorax and its return on the 

 flow of blood to and from the heart and so on the blood- 

 pressure 499 



312. The effects of the expansion and return of the thorax on the flow 



of blood through the lungs 502 



313. The effects on the circulation of artificial respiration . . .503 



314. An action of the cardio-inhibitory centre synchronous with that of 



the respiratory centre 504 



315. The effects of impeded respiration on the circulation in general. 



Traube-Hering curves. The circulation in asphyxia . . .504 



