104 



tary matter, by combining its watery with its fat and oily, parts, is there- 

 fore, extremely compound : it is at once watery, albuminous, oily, alka- 

 line, and saline*. The liver which secretes it, is a very bulky vis- 

 cus, situated in the upper part of the abdomen, and kept in its place, 

 chiefly by its attachment to the diaphragm, of which it follows all the 

 motion. 



The hepatic artery, which the creliac sends off to the liver, supplies it 

 only with the blood requisite for its nutrition : the materials of its secre- 

 tion are brought by the blood of the vena portse. 



This opinion on the uses of the hepatic artery, which I take up with 

 Haller, cannot rest upon the experiments of those who pretend to have 

 seen the secretion of the bile going on, after it was tied. Besides that 

 the position of this vessel makes the operation almost impossible, which 

 gives me reason to doubt if ever it was practised ; and if it were, by in- 

 tercepting the course of the arterial blood carried to the liver, this viscus, 

 even under the received hypothesis, would remain deprived of nourish- 

 ment and of action : and the vena portse would supply it, in vain, with a 

 blood on which it could exert no influence* When this vein is tied, which 

 it is far more easily done than the artery, the secretion of bile is seen to 

 stop; but the experiment which suspends the abdominal venous circula- 

 tion, is too speedily fatal, to justify any conclusive inference. It is on 

 analogical proofs, that the received hypothesis rests, touching the man- 

 ner of the biliary secretion. The hepatic artery, remarkably lessened by 

 the branches it has sent off in its way towards the liver, is to that organ 

 what the bronchial arteries are to the lungs; and in the same manner, 

 the branches of the vena portae, spread through its substance, may be 

 compared to the system of pulmonary vessels. It is still to be confessed, 

 however, that the enormous bulk of the liver, its being found in almost 

 all animals, and the quantity of blood carried into it by the vena portae, 

 compared to the small secretion there is of bile, lead to the belief that the 

 blood sent to it from all the other organs of digestion, undergoes changes 

 there, on which science possesses, as yet, no certain data, though the 

 chemists maintain, that the liver is, in some sort the supplementary 

 organ of the lungs, and assists in clearing the blood of its hydrogen and 

 carbon. 



* " Human bile differs considerably from that of all other animals. Its colour is 

 sometimes green, sometimes yellowish brown, aud sometimes it is nearly colourless. 

 Its taste is not very bitter. It is seldom completely liquid, but usually contains some 

 yellow matter suspended in it. When evaporated to dryness, it leaves a brown mat- 

 ter amounting to about 1-1 1th of the original weight. When this matter is calcined, 

 it yields all the salts which are to be found in the bile. All the acids decompose hu- 

 man bile, and throw down a copious precipitate, consisting of albumen and resin."- 

 Thomson's Chemistry, &c. 

 The following is the analysis of human bile according to BERZEMUS : 



Water, 908-4 



Picromel, 80- 



Albumen, 3' 



Soda, 4-1 



Phosphate of lime, .... 



Common salt, .... 3-4 



Phosphate of soda with some lime, 1 



1000 



Copland. 



