xii CONTENTS. 



Products of the Decomposition of Hcemoglobin. 



PAGE 



350. Haemoglobin splits up into hsematin and a proteid .... 567 

 351. The features of haematin. Hsemin. Methaemoglobin . . . 568 



The relations of the Carbonic Acid in the Blood. 

 352. The carbonic acid of the blood not simply absorbed .... 570 



The relations of the Nitrogen in the Blood. 

 353. The nitrogen simply absorbed . . . -'"'"- . . . 571 



SECTION V. 



THE RESPIRATORY CHANGES IN THE LUNGS. 



354. The relations of the oxygen of the blood to pressure. Association 

 of oxygen with, and dissociation from haemoglobin. The 



problem stated 572 



355. The experimental evidence 574 



356. The relations of the oxygen in laboured breathing and asphyxia . 575 



The Exit of Carbonic Acid. 



357. The exit of carbonic acid determined by the partial pressure in the 



pulmonary alveoli 575 



SECTION VI. 



THE RESPIRATORY CHANGES IN THE TISSUES. 



358. The oxidations of the body take place mainly in the tissues and not 



in the circulating blood. The respiration of muscle . . . 578 



359. The respiration of other tissues. The taking in of oxygen separate 



from the giving out of carbonic acid 580 



360. A summary of respiration in its chemical aspects .... 582 



SECTION VII. 



THE NERVOUS MECHANISM OF RESPIRATION. 



361. Respiration an involuntary act. The efferent nerves, the respiratory 



centre 584 



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

 sidiary spinal mechanisms 585 



363. The action of the centre automatic . . . * . . . . 586 



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



of the vagus nerve. Inhibitory and augmentor effects . . 587 



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

 onism between the two . . ' 591 



