SALICYLIC ACID AND SALICYLATES. 725 



SPECIAL STUDY OF THE DISTRIBUTION OF THE NITROGENOUS CONSTIT- 

 UENTS OF THE URINE AS AFFECTED BY THE PRESERVATIVES. 



INTRODUCTION. 



It is a very common opinion among medical practitioners and phys- 

 iologists that salicylic acid when properly administered has some spe- 

 cific effect upon the excretion of certain of the nitrogenous elements of 

 the urine, notably uric acid. One of the principal difficulties attend- 

 ing investigations of this character heretofore has been the uncer- 

 tainty attending the methods of determination with regard to accuracy 

 as to the quantities of nitrogen present in various forms. Some of 

 these nitrogenous elements are present only in small quantities, and 

 therefore any inherent fault of the method itself or any failure in 

 proper manipulation on the part of the analyst is likely to introduce 

 very serious errors into the results. The data which follow have been 

 obtained in accordance with the methods of investigation which have 

 been described in detail. 



The stud} 7 of the individual data shows often a wide daily variation 

 in the various forms of nitrogenous constituents excreted, and the 

 daily quantit}^ of total nitrogen excreted also shows notable variations, 



The total nitrogen of the urine having first been determined, thfe 

 quantities of nitrogen which were present as urea, uric acid, xanthin, 

 kreatinin, and ammonia were separately determined. The difference 

 between the total nitrogen contained in these bodies and the total 

 nitrogen of the urine represents the nitrogenous elements undeter- 

 mined. On account of the amount of analytical work in connection 

 with the study of the metabolic processes during Series VI, it was 

 found impossible to properly conduct a study of the distribution of 

 the nitrogen in the urine. To remedy this fault a supplemental study 

 was made of four men subsequent to the investigations described as 

 Series VI. 



