10 On the Influence of Air 



Many experiments might here be adduced, but I shall 

 content myself with one related by the ingenious Dr, 

 Gardner. 



" Some years ago, I cut out the heart and part of the 

 large vessels of a turtle, with a view to examine the struc- 

 ture of the parts, and the circulation of the blood in this 

 animal. Having wiped off the blood and other moisture, 

 the heart was wrapped up in a handkerchief; but en- 

 gagements in the way of my profession obliged me to 

 postpone the gratification of my curiosity until absent 

 six or seven hours after it was cut out. When I exa- 

 mined it, there appeared not the least signs of life, it 

 being much shriveled and dried. But on putting it into 

 water, nearly milk-warm, it plumped up, and some parts 

 of it acquired a tremulous motion. Laying it on the 

 table, and pricking it with a large needle, it palpitated 

 several times. The palpitation renewed as often as the 

 needle was pushed into its substance, until it became 

 cold, when it seemed insensible to every stimulus. But, 

 after warming it again in water, it recovered its irritabi- 

 lity, and repeated its palpitations on the application of 

 the needle. Though no motion could be excited in it 

 when cold, yet it moved several times after being mace- 

 rated in warm water." 



The physical power, therefore, of the living fibre, 

 though superior in its force of action to the impulse 

 which excites it, is dependent on the same laws of mo- 

 tion and temperature, by which every particle of matter 

 in nature is actuated. As animal heat and irritability 

 mu^t co-exist, and as, agreeable to the modern doctrine. 



