610 MUSCULAR CONTRACTILITY. 



pieces of muscle were taken from the neck of a 

 recently killed sheep, and placed in water at 

 different temperatures, they contracted sooner 

 and more firmly, in proportion to the quantity of 

 heat applied.* Nor was he ignorant that the 

 blood itself when removed from the body, and 

 therefore from all nervous influence, undergoes 

 contraction, as in the process of coagulation ; and 



* With a view of ascertaining the correctness of his results, 

 I took three pieces of muscle from the neck of a sheep just bled 

 to death, each of them an inch and a half in length, and put 

 them into separate vessels of water, at temperatures of 80, 110, 

 and 120 when the one in the first vessel contracted -J- inch in 

 three minutes ; the second, \ an inch, and the third f , in one 

 minute and a half. The experiment was then varied by placing 

 another piece of the same dimensions in a freezing mixture at 

 17, when it scarcely contracted at all, and was quite frozen in 

 seven minutes. But when transferred to water at 120, it slowly 

 shortened from 1J to half an inch. In accordance with these 

 facts, it was found by Mr. Clift, that by the application of hot 

 water, the heart of a carp was made to contract eleven hours after 

 decapitation and that the muscles of another carp were thrown 

 into a state of violent contractions by the same means, four hours 

 after the brain and spinal marrow had been destroyed. Similar 

 results were obtained by Mr. John Marshall at my request in 

 1840. For he found that, forty-five minutes after the vessels of 

 the neck of a tortoise had been divided, the pulsations of its heart 

 were augmented from nineteen to thirty-six per minute, on raising 

 its temperature from that of his room to 90 that on applying 

 water cooled down to 60, they were reduced to seven beats, but 

 augmented to fifty-two on raising the water to 106, and again 

 reduced to twenty-two per minute, on cooling the water to 90. 

 The heart was then removed from the body, and exposed to the 

 alternate influence of warm and cold water, with similar results, 

 which were also observed on the heart of a salamander. 



