THE ALUMNI JOURNAL 135 



though the amount of carbon dioxide produced has served to indicate 

 the presence or absence of methyl alcohol. 



As oxidising agents, the peroxides, permanganates, chlorates with 

 hydrochloric acid, bichromate-sulphuric acid mixture, chlorine, brom- 

 ine, hypochlorites, mercuric oxide, hot copper oxide, and others have 

 been used. Out of these, the bichromate-sulphuric acid mixture, per- 

 manganate, and hot copper oxide (on copper spiral or gauze) are 

 chiefly employed. 



(a) Hot copper oxide was first used for this purpose by Mulliken 

 and Scudder (*) who state that i in 5 and even 10 parts of methyl in 

 ethyl alcohol may be thus detected, but that methyl esteres, if present, 

 give a reaction for formaldehyde. They modified and improved their 

 method (^) in respect to testing for formaldehyde with resorcinol. 

 This method, modified by S. P. Sadtler (®) was adopted by the U. S. 

 Pharmacopoeia, VIII D. R. Acetic aldehyde is boiled oflf and the liquid 

 tested for formaldehyde with a weak solution of resorcinol and strong 

 sulphuric acid. Upwards of 2 per cent, may be detected. The obser- 

 vations of others that ethyl alcohol will, by oxidation with hot copper 

 wire, yield some formaldehyde, especially when volatile impurities are 

 present, have been confirmed in experiments with this method. After 

 oxidation with hot copper oxide A. B. Prescott (') destroyed the 

 acetic aldehyde with hydrogen peroxide, and tested for formaldehyde 

 with an alkahne solution of phloroglucin, as devised by Vanino (®). 

 In the copper spiral method of L. D. Haigh {"), the liquid after oxi- 

 dation is filtered, acetic aldehyde removed by boiling, and test made 

 with phloroglucinol in a white porcelain dish. The same color was 

 produced even with pure ethyl alcohol. 



The copper spiral method was criticised by E. Jandrier ("), who 

 found that acrolein reacts with resorcinol like formaldehyde, and that 

 traces of furfural will effectively cover relatively large amounts of 

 fqfmaldehyde. Scudder and Riggs (") showed that many organic 

 compounds give formaldehyde on oxidation with copper spiral, pro- 

 nouncing the method unreliable. 



(b) The poiassium permanganate method of P. Cazeneuve was 

 modified by Habermann and Oesterreicher (^-), the oxidation with 

 AY 10 permanganate being carried out in an alkaline solution. Limit, 

 5 per cent. Sangle-Ferriere and Cuniasse (^^) oxidised in sulphuric 

 acid solution with a saturated solution of permanganate, neutralised 

 the liquid and tested with phloroglucinol. Pendler and Mannich (^*) 



