BORIC ACID AND BORAX. 39 



two tables in the quantities which are recovered in the urine, being 

 remarkably low in the case of all the members of the class of Series 

 III. No satisfactory explanation of this variation can be given. Had 

 it occurred in only one instance it might have been attributable to a 

 failure to collect the whole of the urine or to some anatytical error, 

 but, being uniformly low, these explanations are not tenable. Of the 

 total quantity of boric acid given to all the members of the class, 

 namely, 132.9 grams, 84.9 grams are recovered in the urine, a per- 

 centage of 63.88. 



The data for Series IV are given in Table VI. We have here a 

 return to the percentage occurring in the urine shown in Series I and 

 II. The highest amount recovered is in the case of No. 11, namely, 

 89.74, and the lowest in the case of No. 8, 78.68. During this series 

 99.5 grams of boric acid in the form of borax is given in the food, of 

 which 82.55 grams are recovered in the urine, or 82.96 per cent. 



The quantities of boric acid recovered in the individual cases in Series 

 V vary greatly. (See Table VII.) As has been already explained, 

 only J-gram quantities are given during this series of observations, but 

 the exhibition of this quantity is extended over a period of fifty days, 

 so that in normal cases 25 grams of boric acid are administered during 

 this period to each of the subjects. In point of fact, however, in only 

 two instances is this full amount taken, while in a third instance within 

 half a gram of that amount is taken. The largest percentage recovered 

 in any one instance is in the case of No. 4, namely, 84.42 per cent. 

 No. 4, however, completed only about half of the period. The small- 

 est quantity excreted is found in the case of No. 3, namely, 68.44 per 

 cent. Of the 127 grams of boric acid administered during the whole 

 series 95.47 are recovered in the urine, or 75.17 per cent. 



Summarizing the quantity of boric acid given during the whole 

 period of observation, including the five series (Table VIII), we find 

 that it amounts to 607.4 grams. Of this quantity 468.69 grams are 

 recovered in the urine, or, expressed in percentage, 77.16. In con- 

 nection with this determination attention should be called to the fact 

 that the quantitative determination of boric acid in a liquid like urine 

 is attended with considerable difficulties, unless such a length of -time 

 be devoted to it as would render the execution of a large quantity of 

 work impracticable under existing conditions. The methods employed 

 are fully described in the part of this bulletin devoted to the methods 

 of analysis, and it is believed that the data obtained, while not rigidly 

 exact, are satisfactory for the explanation of the metabolic processes. 

 The data show that the great burden of excreting the boric acid from 

 the body falls upon the kidneys. 



In order to determine whether boric acid was lost to any extent by 

 perspiration, one of the assistants in the laboratory carefully extracted 

 with water a set of flannels worn for one hour during a game of ten- 



