ITS FORMATION. 93 



Taking this view of the subject, it would be important to ascertain 

 whether the adjunct which yields glycine or taurine, exists pre- 

 formed (either free or in combination) in portal blood. In regard 

 to the glycine, every attempt to detect it in portal blood has been 

 unsuccessful, although as much as 450 grammes [about 15 ounces] 

 was examined for this purpose ; this experiment cannot, however, 

 be definitely regarded as proving that no glycine occurs in portal 

 blood, since the cause of the negative result may be dependent on 

 the imperfection of our chemical analyses ; but, at all events, the 

 opposite view, in accordance with which the glycine of the cholic 

 acid is first formed in the liver, is not overthrown by this experi- 

 ment, and we shall presently point out the grounds which support 

 the idea that the glycine is produced in the liver from the meta- 

 morphosis of nitrogenous matters. Moreover, we are equally un- 

 able to detect pre-formed taurine in portal blood. 



According to F. C. Schmid,* the ash of portal blood is richer 

 in sulphuric acid than that of blood from the jugular veins; we 

 might be thus led to suppose that the sulphuric acid of the portal 

 blood was applied in the liver to the formation of the sulphurous 

 adjunct, but this is not the case. It is well known that the estima- 

 tion of the sulphur in an ash-analysis is the most uncertain of any 

 of the determinations in analytical chemistry, since it depends on 

 various accessary circumstances (the mode of heating, the presence 

 of carbon hard of combustion, or the absence of alkalies with which 

 the sulphuric acid that is formed might combine), whether more 

 or less sulphur is volatilised. In employing this inexact mode 

 of determination, I was, however, unable to find the difference 

 between the blood of the portal and the hepatic veins, which 

 Schmid observed between that of the portal and jugular veins. 

 The pre-formed sulphuric acid in the water-extract of the portal 

 and hepatic venous blood appears to be variable ; but as a general 

 rule, I always obtained rather more sulphuric acid from the serum 

 of hepatic venous blood than from that of portal blood : the aug- 

 mented quantity in the first case is, however, only relative ; for 

 the serum of the portal vein, in becoming changed into that of 

 the hepatic veins, not only loses much water, but also albumen, as 

 we shall subsequently show. This much may, however, be regarded 

 as certain, that the pre-formed sulphuric acid no more contributes to 

 the formation of the sulphurous adjunct, than it passes into the bile. 

 (See vol. i., p. 444). 



If, however, we compare the quantity of sulphur in the two 

 kinds of blood by the application of the dry method of oxidation, 

 * Heller's Arch. Bd. 4, S. 323. 



