398 Influence of Inanition on Metabolism. 



Sulphur occurs in the urine in at least three different forms: First, 

 preformed sulphuric acid; second, oxidized sulphur which is combined with 

 some organic radical to form the so-called ethereal sulphates; and third, the 

 unoxidized or " neutral " sulphur. Not only did some of the earlier investi- 

 gators fail to recognize clearly the different forms of sulphur or their signifi- 

 cance, but in the records of the determinations which have been made there 

 has been more or less lack of uniformity in the method of expressing the 

 results. Some authors have expressed their data as S, others as H 2 S0 4 and still 

 others as S0 3 . Since but little is known of the nature of the neutral sulphur, 

 it seems most logical to record the total sulphur elimination as S, rather than 

 H 2 S0 4 or S0 3 , and in subsequent reports it will be so expressed. 



In consideration of the fact that much of the earlier work is here presented, 

 and that physiological chemists have not been accustomed to interpret the 

 results of sulphur determinations in terms of sulphur, in all the experiments 

 here reported the old usage is retained. To pave the way for the subsequent 

 expression of the results of analyses in terms of sulphur, the averages for the 

 different days of the experiment are given in heavy faced type in tables 208, 

 210, and 211 as sulphur (S) along with the results expressed as sulphur trioxide 



(S0 3 ). 



From a careful computation of the results as presented, the data for earlier 

 fasting experiments (all calculated on the same basis, namely, S0 3 , for 

 purposes of comparison) are given in table 207 herewith. Unfortunately the 

 determinations on Succi in Florence and Naples did not include the total 

 sulphur, hence there are no data for these fasts regarding the neutral sulphur. 

 E. & 0. Freund (10) reported the total, the inorganic, the ethereal, and the 

 neutral sulphur. 



The results reported by Sadovyen (2) did not include the neutral sulphur 

 and hence are comparable to the results in other experiments in which the 

 inorganic and ethereal alone were determined. 



It has recently been pointed out by Folin 80 that the determination of 

 sulphuric acid as barium sulphate involves technicalities that have in many 

 instances been overlooked. Hence the comparison of the results obtained by 

 different investigators by the determination of sulphuric acid in the urine 

 is somewhat questionable. In fact, it is tolerably clear that much of the older 

 work involves errors which render even the determinations of total sulphur 

 unreliable. Moreover, any errors in the determinations of either total sulphur 

 or ethereal sulphates affect the measure of the neutral sulphur, since the 

 latter is determined indirectly as the difference between the total sulphur and 

 the ethereal (and inorganic) sulphates. 



So far as the inorganic and ethereal sulphur is determined, it is probable 

 that with certain limitations the results may, in general, be compared. 



80 Journal of Biological Chemistry, 1906, 1, p. 131. 



