AtTGUST 11, 1911] 



SCIENCE 



165 



gravity increases in a short time. The 

 purest ether procurable on the market is 

 of 0.718-0.719 specific gravity at 15°, but 

 this absorbs water on exposure to the at- 

 mosphere and rises to 0.720-0.721 specific 

 gravity, when it becomes fairly constant. 



Since the specific gravity of ether is 

 0.7178 to 0.719 at 15° C, those requiring 

 ether of 0.720 specific gravity thus allow 

 minimum amounts of water and alcohol. 

 Unless the ether is dried carefully by 

 means of sodium, for example, and is 

 kept constantly dehydrated by storing 

 over such an agent, or great care is taken 

 in storing it after final rectification, it is 

 practically impossible to maintain the 

 specific gravity originally possessed by the 

 ether. 



The speaker, assisted by Mr. W. A. 

 Hamor, has conducted an extensive in- 

 vestigation on the changes which occur in 

 ethyl ether during storage, and the experi- 

 mental data obtained" lead to the conclu- 

 sion that the oxidation of ether in the 

 presence of moisture is productive of a 

 series of complex conversions, initiated, 

 however, by the formation of hydrogen 

 dioxide. The slow combustion of pure 

 ether in the presence of water, and under 

 such conditions as exist when it is im- 

 properly stored, would appear to occur 

 in the following stages: 



1. The formation of hydrogen dioxide 

 from water and oxygen of the air. This 

 is particularly likely in cases where there 

 is direct exposure to light, and it is more 

 or less activated by contact action. 



2. Dissociation of hydrogen dioxide 

 into water and oxygen, which latter then 

 exerts a direct oxidizing action, resulting in 

 the formation of the following: acetic per- 

 oxide, acetaldehyde and acetaldehyde per- 

 oxide, and eventually acetic acid. The for- 

 mation of acetic peroxide facilitates a series 



' J. Ind. and Eng. Chem., 3, Nos. 5 and 6. 



of oxidations, and by its hydrolysis alone 

 acetic and peraeetie acids are formed. 

 The peraeetie acid then becomes converted 

 into acetic acid and hydrogen dioxide. 

 Therefore it is reasonable to conclude 

 that a continuous cycle of changes occurs 

 in ether during its oxidation and that such 

 changes result in the simultaneous forma- 

 tion and occurrence of peroxidized com- 

 pounds, intermediate (aldehyde) and ulti- 

 mate (acetic acid) resultants. 



Our experimental work seems to estab- 

 lish beyond any doubt the fact that ether 

 of anesthetic grade contains peroxidized 

 compounds after exposure to varying tem- 

 perature conditions and sunlight, in the 

 presence of atmospheric oxygen, for con- 

 siderable periods of time, especially when 

 it is stored in colorless glass vessels or in 

 badly stoppered tin containers. 



Aldehyde is undoubtedly the common- 

 est contaminant of anesthetic ethers, and 

 its presence may account for some of the 

 observations made in practise. It is one 

 of the impurities most likely to be gen- 

 erated by exposing partially filled contain- 

 ers to varying atmospheric conditions 

 for long periods of time. Ether should 

 not be stored in glass vessels for any 

 length of time without being tested for 

 oxidation products before use; and the 

 tin containers should be of such capac- 

 ity that they need not be opened with- 

 out being emptied when the ether is em- 

 ployed for anesthetic purposes. 



With regard to the acidity of the vari- 

 ous anesthetic ethers on the American 

 market, it may be said that none that we 

 have examined contained acids (sulphur- 

 ous, sulphuric, acetic) in what may be 

 termed injurious amounts, since the 

 amount present never exceeded 0.002 

 gram of acetic acid per 100 c.c. of the 

 sample in any case. The degree of acidity 

 is liable to vary more or less in both diree- 



