12 



THE NEW YORK JOURNAL OF PHARMACY 



the preservatives and loss by ferment- 

 ation are evident in cases of chloro- 

 form, thymol and gallic acid ; probably 

 with phenol, sodium arsenite and ether 

 also. Salicylic acid, sandalwood oil 

 and boric acid seem best for the pres- 

 ervation of dextrose. With uric acid, 

 the changes are apparently great with 

 ether, hydrogen peroxide and sodium 

 benzoate ; however, it must be remem- 

 bered that these preservatives, and also 

 thymol, interfere with the analysis of 

 uric acid by the uricometer method, 

 thus giving rise to the discordant data. 



The ammonia data, as direct esti- 

 mates of the hydrolysis of urea, are 

 probably the best indications of the 

 comparative antiseptic value of the 

 dififerent preservatives, not only on 

 account of the refinement of analysis 

 of ammonia but also on account of the 

 non-interference of preservatives with 

 its determination. However, it must 

 be remarked, that, although sulfuric 

 acid yields but little ammonia, it trans- 

 forms, possibly by oxidation, excep- 

 tional quantities of urea. 



Considerable uniformity is met with 

 in the analysis of urea, sulfuric acid 

 alone seeming to have large destruc- 

 tive effect and formaldehyde being 

 next with low results on account ot 

 precipitation.^ 



With creatinine there mav be either 

 an increase or a decrease- of concentra- 

 tion. The increase resulting in acidic 

 solutions involves the hydolysis of 

 creatine to creatinine. Since the 

 colorimetric method of analysis of 

 creatinine was employed, preservatives 

 like thymol, phenol, ether, etc., gave 

 too large readings of concentration. 



iVide infra. 



The decrease, resulting usually from 

 the alkalinity of the solution, involves 

 a transformation of creatinine to crea- 

 tine ; a decrease may also result, 

 through precipitation, as in the treat- 

 ment with sulfuric acid.- 



The Respective Preservatives.— (i) 



Salicylic acid is the best preservative 

 of those studied. This excellence of 

 salicylic acid for urine was described 

 by Jordan.^ It is of further interest to 

 observe that, finding alkaline salicylate 

 to have no reducing or solvent effect 

 on copper, Kendall* uses it instead of 

 alkaline tartrate as the medium for 

 oxidation of sugars. Its use, therefore, 

 as a preservative will not interfere with 

 the estimation of dextrose in urine by 

 copper solutions. 



(2) Though chloroform preserves 

 urea, and therefore ammonia, it is in- 

 effective with glucose and creatinine.'^ 



(3) Thymol, though used frequently 

 as a preservative for urine, does 

 not seem to merit the value placed 

 upon it; for, although little sediment 

 is formed when it is used, and even if 

 it had considerable bactericidal power, 

 which is doubtful, its presence inter- 

 feres with too many reactions involved 



2Edlefsen, Munch, med. Wochsch., 55, 1615, 

 2524. 



^Biocheni. J., 5, 274; Proc. Roy. Soc. Med. 

 Pharm. Sec, 5, 26. See also Luchrig and 

 Sartori, Pharm. Ccntrh., 49, 934; Dafert and 

 Haas, Arch. Chem. Mikros., 1908, i ; E. von 

 Meyer and H. Kolbe /. prakt. Chcm., 12, 178. 



4This Journal, 34, 320. 



°The loss of creatinine when chloroform 

 was used as a preservative was observed by 

 Benedict and Myers, Am. J. Physiol, 18, 380. 

 See also Gill and Grindley. This Journal, 

 31, 707. The unsatisfactory preservative 

 power of chloroform for sewage was re- 

 marked by Lederet and Hommon, Eng. Record, 

 62, 319; /. Am. Pub. Health Assoc, i, 267. 



