xvi RESPIRATION 



CHAPTER X. BLOOD CIRCULATION AND BREATHING 257 



Intimacy of connection between circulation and breathing, 257. The mosl 

 immediate need for circulation is the need for oxygen and for removal of COz, 

 257. The local circulation rates must be correlated in the main with these 

 needs, 258. Special value of experiments on man, 259. Experiments of Loewy 

 and von Schrotter with lung catheter, 260. Experiments of Krogh and Lind- 

 hard by the nitrous oxide method, 262. Yandell Henderson's experiments on 

 dogs, 263. Experiments on "heart-lung preparations," 264. New method in 

 which the whole of the lungs are used as an aerotonometer, 264. Results in 

 man during rest and work, 265. The circulation rate is rapid during rest, and 

 does not increase in direct proportion to work, 268. The oxygen consumption 

 per heartbeat and its significance, 269. The venous blood from different parts 

 of the body, 270. Significance of this as regards the mixed venous blood under 

 different conditions, 270. General conclusion as regards local regulation of 

 blood flow, 271. Yandell Henderson's experiments on local circulation and 

 COz pressure, 272. Evidence that excessive artificial respiration causes slowing 

 of the circulation and great local anoxaemia, 272. With moderate increase of 

 COz percentage in the inspired air the circulation does not increase with the 

 breathing, 273. But with great increase of COz percentage the circulation in- 

 creases, 274. Increase in oxygen pressure slows the circulation, 274. With 

 great deficiency of oxygen there is increase in the circulation, 275. Effects of 

 forced breathing and muscular exertion on venous blood pressure, 275. Gen- 

 eral conclusion as to regulation of local and general circulation, 276. Com- 

 parison of regulation of circulation with regulation of breathing, 277. Part 

 played by the heart in the circulation, 278. Regulation of heart's action, 278. 

 Coordination of contraction of muscular fibres of auricles and ventricles, 278. 

 Start, spread, and frequency of each contraction, 279. Regulation of filling of 

 ventricles, 279. Nervous regulation of frequency of heartbeat, 279. Regula- 

 tion of blood distribution, 281. Contractility of arteries, veins, and capillaries, 

 281. Vasomotor regulation of arterial and venous blood pressure, 283. 

 Abnormal defects in circulatory regulation, 284. Valvular defects and breath- 

 ing, 286. Nervous defects and breathing, 286. Loss of blood and its treat- 

 ment by gum-saline injections, 287. The condition of "shock," 288. Yandell 

 Henderson's investigations, 288. Shock from absorption of poisonous disin- 

 tegration products, 289. Regulation of blood volume, haemoglobin, and rate 

 of pulse and respiration in animals of different sizes, and after loss of blood or 

 transfusion, 290. Evidence that the haemoglobin percentage of the blood de- 

 pends on the oxygen pressure in tissue capillaries, 293. Chlorotic "anaemia" 

 and breathing, 297. Addendum. Further experiments on the circulation in 

 man, 298. 



CHAPTER XI. AIR OF ABNORMAL COMPOSITION 300 



Outside air of country and towns: effects of impurities, 300. Air of occupied 

 rooms. Common impurities and their effects, 302. Effects of temperature, 

 moisture, and movement of air, 303. General standard of air purity, 305. 

 Critical wet-bulb temperature, 305. The katathermometer, 306. Escape of 

 lighting gas and conditions determining their danger, 306. Importance of pro- 

 portion of CO in lighting gas, 310. Air of mines. Abnormal constituents 

 present, 311. Black damp: composition, sources, and properties, 311. Fire 

 damp: composition, sources, and properties, 313. Afterdamp from explosions 



