102 Mr. Everitt on preparing Hydrocyanic Acid 



several sources I found acid containing only 1*4' per cent. 

 These samples I procured from the several shops personally, 

 and asked for Scheele's strength. They were assayed within 

 24 hours after they were in my possession, both by the nitrate 

 of silver and the oxide of mercury method, and the results in 

 no cases varied more than y\yth of a grain from each other. 

 Now it is true we have no fixed standard, and therefore it is 

 impossible to say whether Allen and Co.'s is too strong or 

 the others too weak ; but thus much is certain, that if a me- 

 dical man were pushing the exhibition of hydrocyanic acid 

 gradually to a maximum dose, the prescriptions being carried 

 to a shop where the acid had only 1-4 per cent., and then by 

 some accident or other cause taken to where Allen's acid was 

 used, a sudden and I fear a fatal increase would be the result, 

 for more than a triple quantity would be taken. For the pos- 

 sibility of a fatal accident, I need only refer to the case of 

 seven individuals near Paris being killed by a slightly in- 

 creased dose, recorded in all the medical periodicals a few 

 years since. 



(9.) On the same evening I called the attention of the 

 members of the Medico- Botanical Society to the method for 

 procuring medical hydrocyanic acid recommended by Dr. 

 Thomas Clarke, by cyanide of potassium and tartaric acid; a 

 method which can now be employed by any one, since Mr. 

 Laming has brought into the market a very pure salt. From 

 very numerous trials, I find that the procuring of this salt, 

 the cyanide of potassium perfectly pure, must be expensive; 

 and I have never been able to procure it strictly in this state 

 without using alcohol to crystallize it from : and many che- 

 mists, I find, (see Mr. Barry's paper above alluded to,) object 

 to it, from its being so excessively deliquescent, and hence 

 rather unmanageable, and also to the liability of this highly 

 poisonous salt being mistaken for other white salts on their 

 counters. This latter objection, I must say, is hypercritical : 

 if people will be careless, there is no means of preventing mis- 

 takes, and I conceive the objection of Mr. Barry applies with 

 tenfold force to many arrangements of a druggist's shop, where 

 we often see tincture of opium flanked right and left by other 

 dark tinctures; and who that has manipulated has not caught 

 himself laying hold of, and using one acid, &c., for another 

 when the mind is also at work ? 



(10.) I have made many trials as to the practicability of 

 applying the cyanide of silver and dilute hydrochloric acid 

 for procuring medical hydrocyanic acid. The cyanide of silver 

 presents many advantages : it is perfectly stal)le, being neither 

 affected by light nor moistuve; its purity can be very easily as- 



