SALICYLIC ACID AND SALICYLATES. 433 



capsules. In the case of the preservatives employed, however, which 

 in the quantities used produced no such effects, the objections are 

 entirely groundless. A preservative administered in this way at the 

 time of the meals, as was always the case, is at once thoroughly 

 incased in the food, is rapidly mixed with the contents of the stomach 

 during the process of digestion, and could not in any way exert any 

 injurious effect by reason of the form of its administration. More- 

 over, this method of exhibition in connection with injection into the 

 blood is one commonly followed in medical and pharmacological 

 experiments. 



QUANTITY OF THE PRESERVATIVE. 



It will be seen that the quantities subjected vary from 210 milli- 

 grams a day at the beginning of the preservative period to as much 

 as 2 grams a day at its close, the object in this arrangement being to 

 determine progressively the limit of toleration for ordinary medicinal 

 doses. With a substance whose activity is as limited as that of sali- 

 cylic acid, it is evident that it would be impossible within any reason- 

 able time to secure any idea of its physiological effect by administering 

 mere traces of the reagent. On the other hand, the quantity used, 

 namely, 30.85 grams, over a period of thirty days, an average of a 

 gram a day, while not excessive, is sufficient to permit of a study of 

 the effects of this substance upon the metabolic processes. 



EXCRETION OF THE SALICYLIC ACID. 



Tracing the history of salicylic acid in the organism is a somewhat 

 difficult procedure. Soon after the exhibition of salicylic acid it or 

 its derivatives appears in the urine, and it is evident that the kidney 

 is the principal excretory organ. Owing to the changes in the com- 

 position of the salicylic acid resulting in the formation of salicyluric 

 acid and other decomposition products, a comparison of the amounts 

 excreted in the urine with the quantity given is a difficult operation. 

 Table III shows in milligrams the quantity of salicylic acid adminis- 

 tered and the amount thereof recovered in the urine. In the course 

 of five days after the cessation of the administration of the salicylic 

 acid nothing but a mere trace was found in the urine. In fact, in some 

 cases only traces were left after four days. 



In this connection attention is called to the difficulties attending the 

 exact determination of salicylic acid and the products obtained there- 

 from in its passage through the bod}^. The method used in these 

 investigations for determining salicylic acid is as follows. 



METHOD FOR DETERMINING SALICYLIC ACID IN THE URINE. 



Make alkaline with sodium hydrate 25 or 50 cubic centimeters of 

 urine, according to the amount of salicylic acid administered, and 

 evaporate, with the addition of a little sand, to a thick sirup. Rub 

 this mass with a pestle, after adding 50 cubic centimeters of 98-99 per 



