164 THE ALUMNI JOURNAL 



moments with considerable force and noise. This ingenious device 

 has probably prevented many explosions which might have been more 

 or less serious. Glass manufacturers are to-day making bottles with 

 a ridge within the neck of the bottle. After the corks are intro- 

 duced they naturally swell and fill this crevice, overcoming any pres- 

 sure from within. 



A pure solution of peroxide without preservatives decreases in 

 strength under ordinary conditions at an average rate of about seven- 

 twelfths of a volume per month. Preservatives retard this decrease 

 considerably. It is evident that a number of manufacturers believe 

 that a solution of peroxide keeps best when strongly acid, as many 

 brands are 'found to be above the U. S. P. standard in this respect. 

 The Pharmacopoeia allows for every 25 cc. of tenth-normal alkali, 

 about 0.049 P er cent, in terms of sulphuric acid. Excessive acidity 

 is unnecessary as a properly made solution will keep if only slightly 

 acid. Care must be taken, however, to allow for any neutralization 

 by the alkalinty of the glass bottles. 



Decomposition of peroxide may be occasioned by the slightest trace 

 of impurities. If a bottle of peroxide is stored upside down or in 

 an inverted position, decomposition takes place more rapidly, as the 

 solution comes in contact with the cork. Bright light and heat 

 causes rapid loss of strength. Dozens and even gross quantities of 

 solution have been known to decompose within a few hours when 

 exposed to the sunlight in a show window. Some manufacturers 

 have adopted a time limit label for their peroxide, thereby being able 

 to trace its age. They place the limit at six or eight months. A 

 solution properly made should keep for a period of six months and 

 even after one year it should not be much below 3 per cent, in 

 strength. Some manufacturers place a batch number on every label 

 and in case of complaint they are able to tell the exact age of the 

 preparation. Some manufacturers who do not use acetanilid decry its 

 use, pointing out the injurious effects of this article on the system 

 and its heart depressing properties, etc.. while other manufacturing 

 agents who use this preservative in its defense claim that acetanilid 

 adds to the preservative action of peroxide. The small amount 

 present, however, can hardly have any effect one way or the other 

 and these arguments can only be regarded as advertising talking- 

 points. Sample of peroxide taken from the same batch, or bottled 

 at the same time under the same conditions, stored in the same posi- 



