RESPIRATION xv 



on the urine excreted during forced breathing, 195. — True acidosis caused by 

 excessive muscular exertion, 196. — Disturbance^ of blood reaction in nephritis, 

 196. — Ammonium chloride acidosis in man, ig^ — Remarks on indirect methods 

 used for measuring changes of reaction in the blood, 199. — Method depending 

 on the dissociation curve of oxyhaemoglobin, 199. — Method depending on ratio 

 of combined CO2 to free CO2 in blood, 200. — Need for more delicate methods 

 than we possess at present, 202. — Question as to the constancy of blood reaction 

 during normal life, 202. — Action of drugs on the regulation of blood reaction, 

 204. — Reasons why the alveolar CO2 pressure is not perfectly steady during 

 rest, 204. — Effects of meats, 204. — Effects of starvation and carbohydrate-free 

 diets, 205. — The regulation of breathing in man during rest is practically 

 speaking regulation of blood reaction, 205. — Addendum. Recent literature on 

 acidosis and alkalosis, 205. — Definition of acidosis and alkalosis, 206. — Ex- 

 treme delicacy and physiological importance of regulation of reaction in the 

 tissues, 207. 



CHAPTER IX. Gas Secretion in the Lungs. . . 208 



Question as to active secretion of gas by the lung epithelium, 208. — Oxygen 

 secretion by the swim bladder epithelium, 208. — Function of the swim bladder, 

 208. — Biot's discovery of oxygen secretion, 209. — Experiments of Moreau, Bohr, 

 and Dreser, 210. — Jager's discovery of the "oval" in the swim bladder, 211. — 

 Histology of the swim bladder wall and "red body," 214. — Probable function of 

 the "red body," 214. — Gas secretion in Arcella. Experiments of Bles, 216. — 

 Implications of secretion generally, 217. — Ideas of Johannes Miiller on secre- 

 tion, 218. — Apparent gas secretion in Corethra larvae, 220. — Ludwig and 

 Pfliiger on gas secretion by the lungs, 220. — Experiments of Bohr and Fredericq, 

 221, — Method and experiments of Krogh, 222. — Carbon monoxide method of 

 measuring arterial oxygen pressure, 224. — Fallacies in earlier measurements, 

 225. — New experiments on animals. Conclusions, 226. — New experiments on 

 men. Method, 229. — Result that secretion is completely absent during rest 

 under normal conditions, but present under conditions producing want of oxy- 

 gen in the tissues, 233. — Experiments after acclimatization on Pike's Peak, 236. 

 — Evidence of constant active secretion, 237. — Indirect evidence of oxygen 

 secretion, 238. — Experiments of Briggs, 240. — Experiments in a respiration 

 chamber at normal atmospheric pressure, 241. — Acclimatization experiments in 

 a steel chamber, 242. — Cause of difference between results by carbon monoxide 

 and aerotonometer methods, 243. — Reason why the percentage of oxygen satura- 

 tion of the arterial blood is considerably less at high altitudes before acclimatiza- 

 tion than corresponds to the oxygen pressure of the alveolar air, 244. — Bohr's 

 method of measuring the rate of diffusion of gases from the alveolar air into 

 the blood, 245. — Experiments of A. and M. Krogh by this method, 246. — 

 Paralysis of oxygen secretion under pathological conditions, 247. — Direct evi- 

 dence that during hard muscular work at normal atmospheric pressure diffusion 

 of oxygen is quite insufficient to saturate the arterial blood with oxygen, 247. — 

 Question of active excretion of CO2 by the lungs. Krogh's experiments, 247. — 

 Reasons for suspecting that active secretion of CO2 may occur under certain 

 conditions, 248. — Comparison of oxygen secretion by the lungs with glomerular 

 secretion by the kidneys, 250. — Reply to some recent criticisms of the evidence 

 for oxygen secretions, 251. — Addendum. Recent experiments of Barcroft and his 

 co-workers, 253. 



