M. Simon further observed, that if the hepatic ducts were alone tied, the liver became choked up and filled with globules of a green tint, which colour was diffused over the whole surface of the organ; and what was very remarkable, that from ten to twenty hours after this experiment, the animals discharged absolutely green matter of the colour of bile, with which the liver was overloaded, a result which would. seem to have proceeded from a vicarious secretion of the kidneys. In opposition to these experiments, we are bound to adduce the case related in the Philosophical Transactions, by Mr. Abernethy, and to which the physiologist will attach all the importance which can be fairly given to evidence furnished by monstrosity. The body of the infant, which forms the subject under inquiry, was found to measure two feet in length, and appeared of the age of about ten months. Its muscles were large and firm, and covered by a considerable quantity of healthy fat, and the general aspect of the body implied that the child had possessed much vigour. The liver was of the ordinary size, but had not the usual inclination to the right side of the body; it was situated in the middle of the upper part of the abdomen, and nearly an equal portion of the gland extended into either hypochondrium.

The gallbladder lay collapsed in its usual situation, and, although rather smaller than usual, presented a natural structure; it contained about a teaspoonful of bile, resembling in colour the bile of children, being of a deep yellow; it was also bitter, but not so acridly and nauseously bitter as common bile. But in this infant the vena portarum terminated in the inferior cava, and the entire supply of the liver was derived through an hepatic artery of an extraordinary size. Dr. Saunders1, who has devoted much attention to the investigation of the liver, observes, that as the function of the vena portarum differs from that of other organs, so has it been supposed to possess certain peculiarities of structure; but that the only marked difference consists in its tunic being thicker, in proportion to the capacity of its canal, than that of a common vein.

40. From the sinus of the vena portarum, three principal branches usually take their origin: these, by forming subordinate ramifications, in a regular series, at length arrive at their terminations, which are of two distinct kinds; the one with respect to the circulation of the blood; the other, as connected with their economy as secreting vessels. In the first point of view, they inosculate with branches of hepatic veins, and, through that channel, return to the inferior cava all that blood which is not employed in the business of secretion. It appears, therefore, that the hepatic veins are the common recipients of the contents of the hepatic artery, and likewise those of the vena portarum. The secreting termination of this vein is the beginning of the hepatic ducts, which, Dr. Fordyce has observed, have improperly been called pari biliarii; for how can we, says he, with propriety, call a tube of many inches in length a pore? These ducts must be exceedingly minute at their origin, since they preclude the admission of the red globules. They gradually enlarge by a union of branches, until at length they pass out from the liver, and form the trunk of the hepatic duct.

From the side of this rises another tube that leads into the gall-bladder, and the union of the two constitutes the common duct, or ductus communis choledochus; through which, it is obvious, that either the bile arising from the liver immediately, or that part of it which has stagnated for some time in the gall-bladder, may pass into the duodenum.

1 A Treatise on the Structure, Economy, and Diseases of the Liver, by W. Saunders, M.D.

41. With respect to the chemical changes which the blood undergoes during its passage into bile, we are entirely ignorant; nor are we acquainted with any of the affinities by which the transmutation can be effected.

42. The liver is plentifully supplied with absorbents, which take their origin from every part of its substance, but more especially from the branches of the hepatic duct: this latter circumstance renders it probable that the bile loses a quantity of its aqueous particles as it passes through these passages, and changes from a diluted to a concentrated state.

43. The liver is supplied with nerves, which arise principally from the hepatic plexus, and enter the substance of the liver with the hepatic artery.

44. M. Majendie states, that the secretion of bile appears constant; for, in whatever circumstances an animal is placed, if the orifice of the ductus choledochus is laid bare, this liquid is seen to flow, drop by drop, at the surface of the intestine: but we are not to conclude that, in the living body, its discharge into the duodenum is uniformly progressive, and without interruption; on the contrary, the termination of the duct will be occasionally pressed upon, during the peristaltic action of the intestine; at which periods the duct will suffer a degree of distention, and the bile will find its way through the cystic duct into the gall-bladder. This effect will, in some measure, be promoted by the oblique manner in which the common duct perforates the intestine, although the more obvious utility of such an arrangement is to prevent the regurgitation of bile from the duodenum. To prevent the evils which must arise from a distended state of the gall-bladder, this viscus is so situated as to be pressed upon by the stomach: I also entertain but little doubt that, in such a morbid condition of this receptacle, an irritation is communicated to the stomach, by which vomiting is produced, which must effectually contribute to the expulsion of its bile.

M. Majendie has generally found it empty in animals that have died by the effect of an emetic poison. It seems very doubtful whether its coats are endowed with muscular powers to eject its contents.