560 WASTE-PRODUCTS 



Neutral Sulphur compounds in which the sulphur is not present as a 

 sulphuric acid radical. 



These three fractions have been found by Folin to vary in a char- 

 acteristic manner with the abundance of proteins in the diet. On high 

 and low protein diets respectively the following daily output of the 

 various sulphur-containing excreta was observed: 



Protein-rich diet. Protein-poor diet. 



Volume of urine . 1170 c.c. 385 c.c. 



Total nitrogen . . 16.80gm. 3.60gm. 



Total sulphur (SO) 3.64 " 0.76 " 



Inorganic SO 3 . . 3.27 " (90. per cent.) 0.46 " (60.5 per cent.) 



Ethereal SO 3 . . 0.19 " ( 5 . 2 per cent.) 0.10 " (13.2 per cent.) 



Neutral SO 3 . . 0.18 " ( 4 . 8 per cent.) 0.20 " (26.3 per cent.) 



It will be observed that a reduction of the total sulphur output 

 to one-fifth, reduced the output of inorganic sulphates to one-seventh, 

 and of ethereal sulphates to one-half, while the output of neutral 

 sulphur remains unaltered. Folin draws an analogy between the 

 neutral sulphur output and the creatinine output among the nitroge- 

 nous excreta, and regards the neutral sulphur as originating from the 

 degeneration of tissue-protein, the Endogenous Metabolism, while the 

 inorganic sulphates represent the extent of Exogenous Metabolism or 

 the destruction of circulating amino-acids which have not become 

 constituents of living tissue. 



The ethereal sulphates, representing conjugated phenols, indican 

 and so forth, have usually been regarded as indicative of the extent of 

 Intestinal Putrefaction. The relatively slight degree to which they are 

 reduced by a reduction of protein intake to one-half is adduced by 

 Folin as an indication that they may possibly arise from the endog- 

 enous metabolism of tissues. It is to be noted, however, as Hopkins 

 has pointed out, that we have no right to assume that Intestinal Putre- 

 factions are reduced proportionately to the reduction of the protein 

 intake. On the contrary, the proportion of the protein intake which 

 reaches the lower intestine without absorption is as a rule very small, 

 unless it chances to be a form of protein which is indigestible, such as 

 raw egg-albumen, or which contains a large glycocoll-fraction, such as 

 gelatin. A large proportion of the putrefaction in the lower intestine 

 must be attributed to the protein contained in the mucous secretions 

 of the intestine itself. Thus Whipple has shown that toxic proteoses 

 of bacterial origin may be absorbed from an isolated loop of intestine, 

 from which the contents have previously been removed. Hence 

 reduction of the protein intake only reduces one, and not necessarily 

 the larger source of intestinal putrefaction, and the reduction of 

 ethereal sulphates to one-half, by a reduction of protein intake to one- 

 fifth, is probably the utmost that could be expected. We may, there- 

 fore, ascribe to the ethereal sulphates, as to the inorganic sulphates, a 

 primarily exogenous origin. 



Another channel of sulphur excretion is the Bile, wherein sulphur 



