COCAINE, EUCAINE. 25 



The hydrochlorate of each is the salt generally made use of. 



Both of them are toxic, even in very small doses, and great 

 care has to be exercised in their use ; they are readily absorbed 

 into the system from subcutaneous, serous, or mucous surfaces, 

 particularly from the first named. 



Cocaine hydrochlorate is readily soluble in cold or warm 

 water, but decomposes on boiling ; the solutions made use of 

 vary from i to lo per cent. It should always be made fresh 

 when required, as even after a few days the efficacy of the 

 solution is not to be relied upon. If it is absolutely necessary 

 to keep it in solution a small quantity of either salicylic or boracie 

 acid added to it will help to preserve it for a longer time. 



After an injection complete local anaesthesia is produced in 

 from three to five minutes, and lasts about twenty or twenty-five 

 minutes ; its effect is manifested around the seat of injection for 

 a space of from half-an-inch to an inch-and-a-half, so that where 

 a large tumour is concerned injections must be made in several, 

 places. Superficially it can be used to deaden pain when painted 

 on parts (such as the under surface of the abdomen and thighs) 

 where the skin is thin, but on the thicker parts its external use 

 on the unbroken skin is not encouraging. On the cornea of 

 the eye its effect is splendidly shown in from one to three 

 minutes. 



Eucaine hydrochlorate, when used alone, does not give such 

 good or rapid anaesthetic results as cocaine, except when applied 

 to the cornea of the eye. It is, however, slightly cheaper than 

 cocaine, a solution of it can be boiled and thus rendered sterile 

 without altering its anaesthetic power, and the toxic dose is a 

 little larger. When anaesthesia is produced, too, the effect lasts 

 longer than that of cocaine. A mixture of the two in equal pro- 

 portions is very useful, as by it can be produced the better and 

 more rapid anaesthetic effect of the cocaine, and at the same time 

 the more prolonged anaesthesia and greater security from toxic 

 symptoms which follow the use of eucaine. In order to be on 

 the safe side, the operator should never allow of either cocaine 

 or eucaine more than one-tenth of a grain for each pound of the 



