ITS USES. HI 



composition, cholic acid closely resembles, and indeed is perfectly 

 identical with the true nutritious matters and respiratory elements ; 

 for sugar, dextrin, and lactic acid are far less complex substances, 

 far more oxidised, and far poorer in carbon, than cholic acid, and 

 yet no one entertains a doubt regarding their physiological value 

 in reference to nutrition and the metamorphosis of matter. We 

 cannot perceive why cholic acid should form so striking an exception 

 to this rule. But if we have regard to the teleological objection, 

 according to -which it seems incongruous that this substance should 

 first be removed from the blood in order again to be taken up into 

 that fluid, we may reply to this that many useful and likewise 

 useless substances are repeatedly separated from the blood by the 

 salivary arid gastric glands (as we see in the case of sugar, iodide 

 of potassium, and the salts of ammonia), and are again taken up 

 by it. In the repeated passage of iodide of potassium through 

 the salivary glands, no one can doubt that. the relations of transu- 

 dation peculiar to those organs are responsible for this phenomena. 

 We cannot, however, ascertain what mechanical or chemical 

 conditions in the liver, besides the formation of blood-cells, are 

 necessary for the secretion of cholic acid in the minute biliary 

 canals. The resorption of the cholic acid in the intestine should 

 therefore not be deemed more unnatural or irrational than the 

 resorption of the chloride of sodium which is separated with the 

 bile. We are as unable to understand the special object which 

 nature has in view in the resorption of the cholic acid, as we are 

 to comprehend the metamorphoses which theresorbed biJe appears 

 very rapidly to undergo in the lymphatic vessels or in the blood. 

 If it, therefore, only remains for us to assume that the resorbed 

 cholic acid (as a respiratory element already partially consumed in 

 the organism) contributes its part to the warming of the animal 

 body, we have a further explanation why the perfect exclusion of 

 bile from the intestine (in Schwann's experiments) may prove 

 prejudicial, although very gradually, to the general health of an 

 animal. 



