ACTION OF POISONS. 143 



dose of the poison, a limit to the period there being 

 during which life can be maintained by means 

 of artificial respiration ; 2ndly, on the inflation 

 of the lungs being carefully made* ; 3dly, on the 

 animal being kept in a temperature of not less 

 than 85 or 90 degrees of heat of Fahrenheit's 

 thermometer. This last precaution is of course 

 a matter of greater importance where the animal 

 is of a small size (as in the case of a cat or 

 rabbit), than where it is larger; still it is not 

 to be neglected even in the case of the human 

 subject ; otherwise the animal heat gradually 

 diminishes until it reaches that point at which 

 the action of the heart can no longer be main- 

 tained, when we have the singular result of 

 an animal perishing from cold in the ordinary 

 temperature of the atmosphere. I have not 

 myself known the circulation to continue where 

 the temperature of the interior of the thorax 

 has been below 78 of Fahrenheit ; but an ex- 

 periment is related by Dr. Chossat, in which it 

 had fallen still lower. 



It is needless to multiply examples of the 

 kind. I am, however, induced to record the 

 following experiment, as it derives a peculiar 

 interest from the circumstance of the use of 

 ether and other anesthetic agents having been 

 lately introduced into the practice of surgery. 



* On this subject I have offered some observations else- 

 where. See Lectures illustrative of various Subjects in 

 Pathology and Surgery, page 7. 



