618 INFLUENCE OF TEMPERATURE 



three minutes. But so languid is the circulation 

 in reptiles and fishes, that when decapitated, or 

 deprived of the heart, their cold, pale, watery, 

 and imperfectly organized blood, oozes out by 

 drops ; and is often many hours in escaping from 

 the system in sufficient quantity to destroy life, 

 especially during cold weather.* Again : when- 

 ever the temperature of the human body is raised 

 above the natural standard by immersion in the 

 hot bath, the pulsations of the heart are aug- 

 mented from seventy or eighty to one hundred 

 and forty or more per minute, which is also the 

 case during the hot stage of inflammatory fever. 

 On the other hand, when reduced below the na- 

 tural standard, as during the cold stage of fever, 

 or by immersion in the cold bath, the force and 

 frequency of the heart's action are greatly di- 

 minished. For example, it was observed by Dr. 

 Currie, that on plunging a patient in water at 



* Caldesi found that the heart of a tortoise contracted from 

 thirteen to twenty times per minute ; while Wilford observed that 

 in the boa, the pulsations varied from fifteen to twenty-five per 

 minute ; and Fontana found them from ten to fifty in the frog. 

 But their number and force depend on the temperature of the 

 surrounding medium. For at 47, Spallanzani observed the heart 

 of a serpent to perform ten or twelve beats ; but twenty eight or 

 thirty beats when the air was at 65 and 70. While others have 

 found, that on the approach of winter, they are sometimes re- 

 duced so low as one beat in two minutes. And Dr. Whytt 

 states, that on raising the temperature of a frog to that of the 

 human body, its pulsations augmented from twenty-five to eighty- 

 seven per minute. 



