184 SYNOPSIS OF VETERINARY 



The second or anesthetic stage is characterized by loss of 

 consciousness, sensation, motion and partial loss of reflex action 

 and is that state suitable for operations. 



The stimulating action of the anaesthetic has ceased and there 

 is now depression of the cerebral functions, the motor and sen- 

 sory tract of the cord, and, to -a partial extent, the reflex centers. 



The voluntary muscles are completely relaxed, the sphincters 

 occasionally, the patient lies absolutely motionless, the cornea 

 fails to respond to irritation, i. e., winking is not produced when 

 the cornea is lightly touched with the finger. 



The corneal reflex being among the last to cease and is the 

 test for complete anesthesia. 



Occasionally the muscles are rigid and twitching during this 

 stage of etherization, although sensation and consciousness are 

 absent. 



The pulse is slow, full, and soft, due to lowered blood pres- 

 sure ; the respiration is slow and shallow but regular. 



The temperature falls in consequence of the lessened mus- 

 cular activity and increased heat loss from dilatation of the 

 peripheral blood vessels. 



In the last or paralytic stage, which must be carefully guard- 

 ed against, poisoning is beginning, and there is depression of the 

 three great medullary centers, controlling the heart, respiration, 

 and vascular tension and also the posterior (or lowest) reflex 

 centers of the cord, so that the urine and faeces are passed in- 

 voluntarily. 



Micturition frequently occurs in the first stages of anaesthesia 

 and should not of itself be considered a danger signal. 



The pulse becomes rapid, feeble and irregular ; the breathing 

 is at first stertorous, and then the respiratory movements become 

 shallow and weak, with long intervals intervening between them ; 

 this irregularity is a most important danger signal. The skin 

 often becomes cold and clammy. 



The pupils are usually widely dilated, though death may oc- 

 cur with either dilated or contracted pupils and consequently no 

 dependence should be put in this sign unless there has been a 

 sudden change from one condition of the pupils to the other. 



