xviii RESPIRATION 



CHAPTER XIV. General Conclusions. . . . 382 



The breathing and circulation are so regulated as to keep the diffusion pres- 

 sures of oxygen, and of hydrogen and hydroxyl ions, in the tissues normal, 382. 

 — Breathing and circulation are responses to tissue activity, and do not pri- 

 marily determine it, 383. — Claude Bernard and the regulation of internal en- 

 vironment, 383. — Diffusion pressures and Bernard's "conditions of life,"383. — 

 Diffusion pressure of water on the same footing as that of other blood constitu- 

 ents, 384. — The blood constituents are in continuous active relation with the 

 living tissues, 385. — Comparison of living tissue elements with dissociable 

 chemical molecules, 386. — Conception of the living body as the seat of a system 

 of mutually dependent reversible reactions, 386. — Defects of the mechanistic 

 and "hormone" theories of physiological inter-connection, 387. — The dividing 

 line between biology and the physical sciences, 388. — The fundamental con- 

 ception of biology, and the real work of the biological sciences, 389. — This 

 work illustrated by the investigations detailed in previous chapters, 389. — 

 Real nature of organic identity, 390. — The existence of active maintenance of 

 organic identity is the foundation of medicine and surgery, as well as of physiolo- 

 gy and morphology, 391. — Examination of the argument that the physical con- 

 ception of Nature is truer and more scientific than the biological, 392. — The 

 previous question which is fatal to the physical conception, 394. — Physical 

 reality a superficial sensuous appearance, 394. — In describing biological phe- 

 nomena and putting her questions to Nature, biology must use her own working 

 hypothesis and not those of the physical sciences, 394. — Nature as seen by the 

 biologist, 396. — Supposed evolution from "inorganic" conditions, 396. — Indi- 

 vidual life and life in association, 396. — It is impossible to describe or define 

 conscious activity in either physical or biological terms, 397. — Neither the 

 physical nor biological interpretation of Nature is, in the last resort, more than 

 a practical makeshift, 398. — The rightful practical sphere of physiology does not 

 include distinctively conscious activity, 399. 



Appendix 400 



A. Determination of oxygen capacity of blood haemoglobin by ferricyanide, 400. 

 — B. Determination of oxygen capacity of blood haemoglobin by haemoglobin- 

 ometer, 404. — C. Determination of oxygen and carbon dioxide in blood by ferri- 

 cyanide and acid, 407. — D. Colorimetric determination of percentage saturation 

 of haemoglobin with CO, 418. — E. Determination of blood volume in man 

 during life by CO, 424. 



