366 Dr. Richardson on the possibility of [June 15, 



channels, and to the evolution of force from that combination. The effect 

 of the oxygen, therefore, is extremely limited ; and when introduced in the 

 gaseous form, the distention it produces leads to a certain degree of disor- 

 ganization of structure. I do not at this moment see therefore that 

 oxygen admits of being applied as a direct excitant of the heart ; but it is 

 worthy of remembrance that the element produces temporary excitability 

 when diffused through muscular structure recently rendered inactive. 



Heat as a restorer of the circulatory power. A large number of 

 attempts were made to restore the circulation by means of heat conveyed 

 into the vessels by heated fluids. The phenomena produced were very 

 remarkable, and they have engaged my attention for more than five years. 

 I first observed that when vapour of water (steam) at a temperature of 

 1 30 was driven into the arteries, there was at once rapid and general mus- 

 cular action, the heart participating in the movement, but less actively 

 than the voluntary muscles. 



Injection of heated water. I afterwards used simple water for injection 

 heated to various degrees, from 96 to 130. When water is thus injected, 

 the animal being only a few minutes dead, and the water not being below 

 115 Fahr., the extent and activity of the muscular contractions are even 

 more marked than when galvanism is brought into action, but in the 

 greater number of cases the effect of the warm water ceases in from fifteen to 

 twenty minutes. When the temperature of the air in which the animal lies is 

 below 40, the water will act for so long a period as three hours after death. 

 The water ceases to exert its influence when it infiltrates the cellular tissue. 

 The admixture of salt with the water, so as to raise the specific gravity to 

 the natural specific gravity of the blood, unquestionably diminishes the 

 effect of the heated water ; the muscular contractions are less rapid and less 

 prolonged, although the infiltration into the cellular tissue is prevented for 

 a much more lengthened period of time. I attribute the action produced 

 on the muscles entirely to the heat evolved by the water. 



Injection of blood*. Injection of blood held fluid by alkali, oxidized and 

 heated to 96, was employed. The blood was injected into the carotid in the 

 direction of the heart, the object being to fill the coronary arteries with the 

 fluid. This intention was fully carried out ; but although the animal had 

 been only a few minutes dead, there was no response on the part of the heart. 



In another experiment, blood from the sheep, defibrinated, thoroughly 

 oxidized, and warmed to 115 Fahr., was injected into the arterial system im- 

 mediately after the death of an animal (a rabbit that had been destroyed 

 by chloroform). The right auricle having been opened to allow of the 

 escape of venous blood, no difficulty was experienced in forcing over the 

 oxidized blood, and it returned freely by the veins ; but it did not excite 

 the least contraction. When this transfusion had been carried on some 

 minutes, the blood was replaced by water at 125 Fahr. Immediately as 

 the water found its way round the body, vigorous action of the body was 

 * See note, p. 369. 



