CAUSE OF THE HEART'S ACTION. 615 



after the heart of a recently killed dog had ceased 

 to contract, its pulsations might be many times 

 renewed by artificial inflation of the lungs, at 

 intervals of eight and ten minutes a fact which 

 has been since verified by the experiments of 

 Brodie and many others. Bichat was also fully 

 aware that respiration is essential to the move- 

 ments of the heart ; but so confused were his 

 notions, that he observes in his " Researches on 

 Life and Death," " the heart ceases to beat when 

 the chemical function of the lungs is arrested, 

 because black blood is not of a nature to keep up 

 its action" 



It is generally admitted by Physiologists, that 

 blood is the proximate exciting cause of the 

 heart's action. But that the caloric evolved in 

 the lungs enables it to produce this effect, is 

 evident from the fact, that when removed from 

 the body, and even deprived of blood, its con- 

 tractions may be many times renewed and sus- 

 pended, by successive elevations and reductions 

 of temperature, without the influence of oxygen, 

 electricity, or any other known agent. As an 

 example of this, it was observed by Bacon, that 

 the heart of a criminal who had been executed 

 for high treason, when thrown into the fire, con- 

 tracted with such force as to leap up seven or 

 eight times, to the height of about 18 inches at 

 first. (Hist, of Life and Death.) It was also 

 ascertained by John Hunter, that when three 



s s 



