266 EXPERIMENTAL INVESTIGATION OF THE ACTION OF MEDICINES. 



stopped with white wax. By means of the screw g the stop- 

 cock may be fastened to the rod E of the rabbit-hold in Fig. 1. 

 The tubes D and d' may either be attached by pieces of india- 

 rubber tubing to tubes of a bottle such as v, or they may be 

 themselves passed through the cork and a small piece of glass 

 tubing long enough to reach the bottom of the bottle attached 

 to d'. By then simply turning the stopcock, pure air may be 

 passed direct to the lungs through c\ r, and c, or it may be 

 loaded with vapour by passing it through d' into the bottle, and 

 then up through D and c to the lungs. 



III. Artificial Circulation: Investigation of Blood- 

 Pressure, 



{British Medical Journal, 1871, June 3, p. 5S1.) 



Artificial Circulation of Blood. — Circulation of Warm and of Cold Blood. — 

 Fever. — Mode of Conducting Artificial Circulation. — Application of tliia 

 Method to Pharmacological Investigations. — Schema of ihe Circulation. — • 

 Circulation in the Living Body. — Importance of the Arterial Elasticity. — 

 Arterial Tension or Blood-Pressure. — Oscillations in it produced by th»^ 

 Heart and Respiration. — Causes of Variation in the Blood-Pressure. — 

 Influence of Nerves upon it. — Cardiac Granglia. — Inhibitory Nerves of Heart. 

 — Quickening Nerves of Heart. — Vaso-niotor Nerves. — Vaso-inhibitory 

 Nerves. — Action of Counter-irritants. — Tabular View of the Causes of altered 

 Pulse-Rate and Blood-Pressure. — Application of this to Pathology. — Experi- 

 mental Examination of Blood-Pressure. — Forms of Manometer. — Kymogra- 

 phion. — Mode of using the Kymographion. — Reduction of the Kymo- 

 graphion Tracings. — Mode of recording Experiments. — Graphic Method of 

 representing Experiments. 



Artificial Circulation of Blood. — A constant supply of arterial 

 blood to all parts of tlie body is necessary to preserve their 

 vitality ; and if the supply to any part be cut off by stopping its 

 circulation, that part will die. Thus, if the circulation be 

 stopped in an arm or leg by tying its arteries, or through 

 their becoming plugged by emboli, mortification, or death of 

 the part, ensues ; and if the heart cease to beat, and the circu- 

 lation be thus stopped in all parts of the body, they all die. 

 But, if we supply arterial blood artificially to any one part, we 

 may keep it alive at least for a certain time after the rest of 

 the animal is dead ; and the muscles may be made to contract, 

 the lungs to excrete carbonic acid, the lymphatics to pour forth 



