GENERAL ANESTHESIA. 73 



large or a small animal, he exerts his strength to rid himself of 

 the apparatus and regain his freedom of motion. 



These manifestations are, however, but of short duration, and 

 are soon followed by a state of passiveness, the respiration be- 

 coming easier, the cough disappearing and his energy subsiding ; 

 and in short, he is subdued. The eye then assumes its character- 

 istic expression, its brilliancy is lost, it is wide open, the pupils 

 slowly dilate, the gaze becomes fixed, the sensibility of the cornea 

 is lost, and the light ceases to effect it. The mouth becomes 

 more or less loaded with saliva; the pulse, which must be carefully 

 noted by an assistant, becomes slow and weak, the respii-ation 

 returns to its normal condition ; the state of complete anesthesia 

 has been reached, and the patient, in happy unconsciousness, is 

 ready for the surgeon. 



The time required to reach this condition varies with the sub- 

 ject, and especially with the quality of the drug administered. The 

 average period is from one to five minutes in small animals, and 

 from ten to fifteen in the large. In some few cases, however, half 

 an hour may elajDse before complete insensibility is produced, and 

 again animals are encountered with peculiar idiosyncrasies, which 

 remain entirely refractory, and successfully resist every attempt 

 to reduce them to insensibility ; a statement equally true when 

 applied to human patients. 



The duration of the Anesthesia. — Some animals remaining 

 under the influence only for a few minutes, sometimes from fifteen 

 to thirty or forty, it becomes necessary to prolong the insensibil- 

 ity by renewing the inhalation, and the}' must, therefore, be con- 

 tinued until the completion of the operation. Recovery from the 

 anesthetic state does not always take place immediately and per- 

 fectly. As the effect begins to subside, the animal, having parti- 

 ally regained his senses, begins to move his eyes, raises his head, 

 perhaps allows it to fall back slowly on the bed, lying flat on his 

 broadside ; then his legs begin to move, and presently he attemj)ts 

 to spring suddenly to his feet. He may succeed in doing so, but 

 again, his muscles may not have yet recuperated their power of 

 full action, and there may be danger of his experiencing a heavy 

 fall on the bed. His condition is one of drunkenness, and he re- 

 quires to be watched, and, if necessary, aided, in order to prevent 

 him from injuring himself by efforts beyond his strength while 

 in a state of weakness of which he is unaware. 



