APPENDIX. 



EXPEEIMENTAL INVESTIGATION OF THE 

 ACTION OF MEDICINES. 



V. — Kespiration. 



(Reprinted from the British Medical Journal^ January 2, 1875.) 



[This Lecture ought to have followed on at the end of Lecture lY on p. 322, 

 but it was accidentally omitted and the omission was not discovered until 

 the whole of this book had been printed off, and it was consequently 

 impossible to insert the Lecture in its proper place.] 



Respiration in Unicellular Organisms ; in the Cells composing higher Organisms. 

 — Distinction between Respiration in an Amoeba and a Fixed Cell. — In- 

 ternal Respiration. — External Respiration. — Internal Eespiration may be 

 diminished or arrested by Diminution or Arrest of the Circulation generally 

 or locally. — Pathology of Fatty Degeneration, by lessening or destroying the 

 power of Haemoglobin to act as an Oxygen -carrier, {a) Action of Carbonic 

 Dxide ; (i) Action of Nitrites ; Action of Phosphorus. — Examination of the 

 effect of Drugs on Haemoglobin. — Colour. — Spectrum — Reducing Agents. 

 — Absorption of Oxygen. — Action of Carbonic Oxide. — Ozonising Power of 

 Blood. — Formation of Acid in Blood. — External Respiration. — Respiratory 

 Movements. — Respiratory Nervous Centre ; Excitants to this Centre. — 

 Venosity of Blood. — Dyspnoea. — Apnoea : two opposite meanings of this 

 term. — Effect of temperature on this Centre. — Effect of Drugs : Tartar 

 Emetic, Chloral, Opium. 



There is a great deal of truth in the oft-repeated comparison 

 between an animal body and a steam-engine. In both, the 

 motion which is their characteristic function is kept up by 

 combustion, and for combustion there is necessary a free 

 supply of fuel and a free supply of oxygen. Simple organisms, 

 such as the amoeba, which consists of a single cell or minute 

 mass of protoplasm only, derive their oxygen, as well as their 

 nutriment, from the fluid in which they swim, and the 

 individual cells which compose the tissues of the higher 

 animals are nourished in much the same way. As Bernard 

 strikingly puts it, " we do not live in air " any more than a 

 number of amoebae swimming about in a glass of water live 



2 T 2 



