HANDBOOK OF PHYOLOGY. 



the blood, and ejection from the body without further change. Probably 

 all the bile secreted in foetal life is incorporated in the meconium, and 

 with it discharged, and thus the liver may be said to discharge a func- 

 tion in some sense vicarious of that of the lungs. For, in the foetus, 

 nearly all the blood coming from the placenta passes through the liver, 

 previous to its distribution to the several organs of the body; and the 

 abstraction of carbon, hydrogen, and other elements of bile will purify 

 it, as in extra-uterine life it is purified by the separation of carbonic acid 

 and water at the lungs. 



Disposal of the Bile. The evident disposal of the foetal bile by excre- 

 tion, makes it highly probable that the bile in extra-uterine life is also, 

 at least in part, destined to be discharged as excrement] tious. The 

 analysis of the faeces of both children and adults shows, however, that 

 (except when rapidly discharged in purgation) they contain very little of 

 the bile secreted, probably not more than one-sixteenth part of its weight, 

 and that this portion includes chiefly its coloring matter in the form of 

 stercobilin, and some of its fatty matters, and to only a very slight de- 

 gree, its salts, almost all of which have been re-absorbed from the intes- 

 tines into the blood. 



The elementary composition of bile-salts shows such a preponderance 

 of carbon and hydrogen, that probably, after absorption, it combines 

 with oxygen, and is excreted in the form of carbonic acid and water. 

 The change after birth, from the direct to the indirect mode of excre- 

 tion of the bile may, with much probability, be connected with a purpose 

 in relation to the development of heat. The temperature of the foetus 

 is maintained by that of the parent, and needs no source of heat within 

 itself; but, in extra-uterine life, there is (as one may say) a waste of 

 material for heat when any excretion is discharged unoxidized ; the car- 

 bon and hydrogen of the bilin, therefore, instead of being ejected in the 

 faeces, are re-absorbed, in order that they may be combined with oxygen, 

 and that in the combination heat may be generated. It appears that 

 taurocholic acid may easily be split up in the intestine into taurin and 

 cholalic acid. The former does not appear in the faeces, but the latter 

 has been found there. So that in part it is excreted, but part is re-ab- 

 sorbed in the intestine and returned to the liver. It is probable that al- 

 though part of this may unite to re-form glycocholic or taurocholic acid, 

 the remainder is united with oxygen, and is burnt off in the form of car- 

 bonic acid and water. 



A substance, which has been discovered in the fasces, and named ster- 

 corin is closely allied to cholesterin ; and it has been suggested that 

 while one great function of the liver is to excrete cholesterin from the 

 blood, as the kidney excretes urea, the stercorin of faeces is the modified 

 form in which cholesterin finally leaves the body. Ten grains and a half 

 of stercorin are excreted daily (A. Flint). 



