PRINCIPLES OF VETERINARY SURGERY 229 



The inspirations will at first be avoided, then several short 

 respirations will be taken as if attempting to avoid the 

 passage of the vapor deeply into the respiratory tract, and 

 finally, when actually forced by threatened asphyxiation, 

 the first deep breath will be inhaled, which may be referred 

 to as the first important event of the phenomenon. It 

 marks the passing of the stage of excitement and the be- 

 ginning of the next period. The pulse will be found full 

 and rapid, the respirations accelerated and now deep, the 

 reflexes of the cornea not altered, the pupil somewhat con- 

 tracted and the eyeball rolling around in its socket. The 

 horse generally whinnies or even screams, the ox bellows 

 and the dog basks or whines. 



2. The Stage of Narcosis. — This stage is often con- 

 founded with the last phases of the preceding and the 

 opening events of the one succeeding. It is, nevertheless, 

 to the observing and experienced ansesthetist, a distinct 

 period intervening between the above mentioned first deep 

 breath and the subsequent first shallow and soft breath, 

 which event isolates it distinctly as a so-called stage of 

 anaesthesia. It is marked by deep and rather harsh inspira- 

 tions, from seven to fifteen in number, depending upon the 

 dilution of the anaesthetic with air. If too much air is not 

 admitted, seven to eight inspirations terminate the stage. 

 The eyes roll in the orbit, the reflexes of the cornea are 

 less acute, the sensibility, if the knife is applied, is but Httle 

 modified and the consciousness is blunted and fast disap- 

 pearing. With the latter event the first real event of 

 anaesthesia proper begins. At this phase, according to 

 Wilheme, the cells of the cerebrum are yielding to the 

 blunting influence of the molecules of the vapor that have 

 been carried to them by the blood vessels. They are being 

 temporarily dehydrated, and the subject passes into a sleep 

 as a consequence of their suspended activity. An examina- 



