xxii CONTENTS. 



PAOB 



§ 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. Phipncea, hyperpnuea, 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 Air 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-IIering curves. The circulation in asphyxia . . . 504 



