THE LIVER. SECRETION OF BILE. 591 



in those judicial inquiries which are directed to the determination of the ques- 

 tion, whether or not an Infant has respired after birth; it having been con- 

 ceived, that the diversion of the current of blood from the Liver to the Lungs, 

 consequent upon the first inspiration, would be sufficient to make a certain dif- 

 ference in their relative weights, if that inspiration had taken place. More 

 careful and extended observations, however, have satisfactorily proved that, 

 although an increase in the weight of the Lungs, and a diminution of that of 

 the Liver, are generally found to exist after respiration has been fully established, 

 they are not by any means constantly produced when the inspirations have been 

 feeble, as they frequently are for some hours or days after birth; whilst, on the 

 other hand, it is not uncommon to meet, in infants that have not breathed, with 

 Lungs as heavy, and Livers as light, as in the average of those which have 

 respired. 1 



630. We have now to consider the conditions under which the secretion of 

 Bile takes place; and one of the most important of these is the character of the 

 Blood with which the organ is supplied. We have seen that there is anatomical 

 reason for the belief that the blood supplied by the hepatic artery is not directly 

 concerned in the secretion ; but that it first serves for the nutrition of the organ, 

 and then, passing into the portal system (in the same manner as does the blood 

 of the mesenteric and other arteries), forms part of the mass of venous blood, 

 from which the secreting cells elaborate their product. This view is borne out 

 by the results of experiment and of pathological observation. For, if the Vena 

 Portse be tied, the secretion of bile still continues, though in diminished quan- 

 tity; and several cases are on record, in which, through a malformation, the 

 vena portae terminated in the vena cava without ramifying through the liver, 

 and in which secretion of bile took place evidently from the blood of the 

 hepatic artery, which had become venous by circulating through the substance 

 of the liver; and this blood appears 2 to have passed into the ramifications of 

 the umbilical vein, which formed a plexus in the lobules, exactly resembling 

 the ordinary portal plexus. It must be remembered, however, that in all these 

 instances, the arterial Blood will become abnormally charged with the elements 

 of bile ; since the blood of the chylopoietic viscera, from which it ought to have 

 been separated, returns to the heart without undergoing any such purification; 

 and the secretion of bile from the blood supplied by the hepatic artery, under 

 such circumstances, cannot, therefore, be considered as proving that the arterial 

 blood is ordinarily concerned in the secretion to the same degree. The fact 

 that this secretion is normally formed from venous blood is a strong indication 

 that one purpose of its separation is the removal of a portion of the products of 

 the disintegration of the tissues : and that a large amount of hydrocarbonaceous 

 matter will remain to be excreted, after the constituents of urea have been sub- 

 tracted from those of albumen or gelatin, has been already pointed out ( 91, vi.). 

 But, again, the position of the Liver in regard to the mesenteric vessels is such, 

 that all the new alimentary materials which are received by them must pass 

 through it and be submitted to its action, before they enter the general current 

 of the circulation; and there are several circumstances which render it probable 

 that it exercises a depurative as well as an assimilating power over these, and 

 that whilst it assists in preparing for nutrition those azotized substances which 

 are capable of being applied to that purpose, and also transforms non-azotized 

 matters into compounds which are more ready to undergo combustion and are 

 thus better fitted for sustaining the heat of the body by respiration, it also elimi- 

 nates certain substances whose passage into the general circulation would be 



1 See Dr. Guy, in "Edinb. Med. and Surg. Journ.," vols. Ivi. and Ivii. 



2 This, at least, was found to be the case in the only instance in which the Liver was 

 examined with sufficient care. See Kiernan, loc. cit. 



