30 



not un frequently sinks to 50 or 55 degrees below 

 zero, while in very hot ones it is sometimes 120 

 or 125 degrees above it making a difference of 

 170 or 180 degrees ; and still the temperature of 

 the human body remains almost unchanged ; 

 and with respect to artificial heat, it has been 

 proved that man can bear with impunity, for a 

 considerable time, a degree of heat which would 

 have roasted him in a few minutes had life been 

 extinct. So also the combination with heat of 

 moisture, so prompt in effecting the decomposi- 

 tion of vegetable and animal substances, when 

 life has deserted them, is quite inert in this re- 

 spect while life continues ; and the same is the 

 case with certain chemical agents, commonly 

 reckoned among the most active, with respect to 

 inorganic substances, but which are quite impo- 

 tent with respect to such as are organic. Of this 

 nature is the substance called the gastric juice, 

 contained in the stomach of animals ; which has 

 no effect upon any thing living, but rapidly acts 

 upon almost any vegetable or animal substances, 

 once divested of life. Thus seeds are uninjured 

 in their passage through the stomach and intes- 

 tines of animals, so long as they retain their life ; 

 worms and other animals are capable of living, 

 for an indefinite time, in the stomach as well as 

 in the intestines ; and a living leech, if acciden- 

 tally swallowed, is never acted upon till life is 

 extinct, when it is rapidly digested, like any other 

 animal matter ; nay, the coats of the stomach 

 itself are not unfrequeritly found to have been 



