92 BILE. 



to other substances. We shall presently see that there are also 

 nitrogenous substances which undergo decomposition in the liver, 

 and we have already (in the first volume) indicated the possible 

 formation of sugar from such decompositions ; and Scherer's dis- 

 covery of inosite (muscle-sugar) renders this view still more probable. 

 Finally, we at present know too little of the extractive matters, in 

 which the portal blood is by no means poor, to feel justified in 

 denying that some of them may be converted into sugar. 



From all this it follows that, unless we would rest satisfied with 

 mere chemical formulae and equations, we are still very far from 

 comprehending the individual stages of the metamorphosis of 

 animal matter, and of recognising the nature of the changes that 

 ensue, and the formation of the different new substances: the num- 

 ber of observations is, however, daily increasing, which must 

 confine the admissibility and number of hypotheses within nar- 

 rower and narrower limits. Thus, from the facts at present in 

 our possession, we cannot decide with certainty which of the 

 hypotheses regarding the formation of cholic acid whether 

 Schmidt's or the one I have propounded approximates the nearer 

 to the truth ; probably neither presents a perfectly correct view 

 of the actual case. The following circumstances seem to tell against 

 Schmidt's hypothesis, and in favour of mine : unconjugated acids 

 containing 9 atoms of oxygen, are, at all events, very rare in che- 

 mistry ; oleic acid yields the ordinary reaction with Pettenkofer's 

 test, which is not the case with the solid fatty acids (of the 

 general formula C n H n _j O 3 ) ; and (which is of most importance) 

 there is far less oily fat (although relatively more solid fat) in the 

 hepatic venous blood than in that of the portal vein. This much 

 only seems fully established from the experiments which have 

 been described, that the liver is an organ in which sugar is 

 formed. 



We can very easily comprehend, and need hardly entertain a 

 doubt, that the nitrogenous adjuncts of cholic acid (Strecker's 

 cholalic acid) are formed from the regressive metamorphosis of the 

 nitrogenous parts of the animal body, and therefore especially 

 from the metamorphosis of tissue : but physiological chemistry 

 should not merely indicate possibilities and probabilities in the 

 animal processes, but it should, at all events for the future, 

 teach us the chemical equations expressing the decompositions of 

 the individual animal substances, and the manner and successive 

 stages in which the metamorphoses occur. We are, certainly, still 

 far from attaining this object, but it is time that we should en- 

 deavour to reach it by all the auxiliaries and forces at our disposal, 



