i6 Surgical Diseases and Surgery of the Dog 



three minutes) and one-half to one ounce suffices to maintain com- 

 plete anesthesia for thirty to sixty minutes. The English or A. C. 

 E. Mixture, consisting of ethyl alcohol one part, chloroform two 

 parts and ether three parts, is an excellent one, producing a narcosis 

 equally as deep as the Billroth but induces greater preliminary ex- 

 citement and salivation. One ounce is sufficient to produce a sleep 

 lasting twenty to thirty minutes. The Hyderabad Chloroform Com- 

 mission found that only by respiration of the concentrated vapor of 

 this mixture could death result with difficulty, and respiratory fail- 

 ure always appeared first. 



The comparative rate of evaporation of the drugs composing 

 the mixtures was studied by Ellis. A definite quantity of ether 

 evaporates in ninety seconds in the usual room temperature of S^'F. 

 The same quantity of chloroform takes five minutes to evaporate 

 under the same conditions, and the same quantity of alcohol takes 

 twelve minutes. If equal parts of alcohol and ether are mixed 

 evaporation of the ether is retarded — instead of seventy-five seconds 

 it takes two minutes, and the remaining alcohol takes another nine 

 minutes. The A. C. E. Mixture evaporates as follows : In the first 

 sixty to seventy-five seconds all the ether with some chloroform is 

 evaporated, in the next three to four minutes chloroform and alco- 

 hol, the first preponderating, and in the following two minutes the 

 rest of the alcohol. 



LOCAL ANESTHETICS. 



Cocaine is the principal local anesthetic. Caution should be 

 exercised in the selection of the drug, as it often contains impurities 

 when it is necessarily disappointing in its action. The crystals 

 should be rather large, colorless and nearly odorless. Great cau- 

 tion must also be observed in its employment, since in overdose it 

 is rapidly toxic. Lethal effect is manifested by mental distress and 

 violent muscular spasm. 



In text-books it is the custom to direct the employment of solu- 

 tions of varying degrees of strength rather than mention the maxi- 

 mum dose which can be safely borne by the dog, a system which is 

 vague and confusing and opens the door to disastrous consequences. 

 Accordingly, no mention is herein made of solutions, that being a 

 matter which must be left to the judgment of the operator, bearing 



