20 TECHNICAL DRUG STUDIES. 



SMITH, KLINE & FRENCH Co. 



We beg to acknowledge receipt of your letter of the 16th with analysis of our hydro- 

 gen peroxid. 



First of all we note that samples 1 and 3, judging from their strength, must be our 

 15- volume peroxid. Therefore, so far as acidity and solids are concerned, they 

 would have to be judged from a different standpoint than the 10 volume, for it must 

 be remembered that 15- volume peroxid, being one-half stronger, the acidity and 

 the solids would necessarily increase in the same proportion. 



This peroxid is plainly branded 15 volumes, and is therefore distinguished from 

 the 10-volume product. 



We are surprised to note that only sample No. 3 contains acetanilid, because we 

 have been putting acetanilid in our peroxid for almost two years, and this would 

 indicate that samples 1 and 2 are very old. If you could let us know the numbers on 

 the packages we could in turn let you know the age of the peroxid, which might be 

 of interest. * * * 



We beg to acknowledge receipt of your letter of January 7 giving us the serial num- 

 bers of packages of peroxid, the test of which you have reported under date of Decem- 

 ber 16. 



We find that the No. 4926 was put up on October 31, 1907, and No. 4935 on November 

 11, 1907. The packages, therefore, were two years old last October and November. 

 It is therefore fair to presume that they were a year old before the tests were begun. 



Since that time peroxid in general, and our peroxid in particular, have been much 

 improved. We think it would be only fair, when the tests are published, to give 

 the date of manufacture and the date of the beginning of the test, because otherwise 

 it would be rather unfair to, for instance, say 15- volume peroxid, and then give the 

 strength found, unless the interval between the manufacture of the goods and the 

 date of the first test was given. We leave this, of course, entirely to your own good 

 judgment. 



Comment by authors. It will be observed that the investigation 

 was begun in October, 1907, and the samples, examined were, there- 

 fore, comparatively fresh. 



FREDERICK STEARNS & Co. 



We are very much surprised to learn that you have found any of our product to 

 run high in solids and so very high in acidity. We test very carefully every batch 

 of this preparation and aim to have it comply with pharmacopreial requirements, 

 except in so far as we, like many other manufacturers of this article, add acetanilid 

 as a preservative, as is stated on every label. This would increase the amount of 

 total solids by the amount of acetanilid so added. In addition to this, the acetanilid 

 also has the effect of increasing the apparent percentage of acid because in the U. S. P. 

 method of assay, the peroxid solution is boiled with the tenth-normal KOH which 

 saponifies the acetanilid, some of the alkali combining with the acetic acid. On a 



25 cc sample, basing calculation upon the amount of acetanilid you found (26.5 

 mg=average), we ought to deduct 0.5 cc tenth-normal KOH from the total number 

 of cubic centimeters required to neutralize the acid, because this amount (0.5 cc) is 

 equivalent to the 26.5 mg acetanilid present in a 25 cc sample of peroxid. 



We understand, of course, that this does not explain the high results you obtained, 

 but it occurred to us that this matter may not have been taken into consideration. 



We have gone over our record of tests for the entire year of 1909 and find that we 

 had but four batches that yielded as much as 30 mg of residue, the next highest was 



26 mg the average for the year being 20.73 mg. Likewise the average acidity for 



