SECRETION OF BILE. 533 



mal, and other secretions would indicate the latter. In those animals which 

 are most constantly ingesting food, we find no Gall-bladder ; for in them, the 

 Bile may be poured into the Intestine as fast as it is formed. In those which 

 only take food occasionally, on the other hand, and which are provided with a 

 Gall-bladder, the Bile, when not required in the Intestine, flows back into that 

 reservoir. This reflux would appear due to the valve-like termination of the 

 Ductus Choledochus in the walls of the Intestine ; by which a certain resist- 

 ance is offered to the entrance of the fluid, unless it be propelled by some 

 decided force. The flow of Bile into the Intestinal tube, when its action is 

 needed there, is commonly imputed to the pressure of the distended Duodenum 

 against the Gall-bladder ; it may be doubted, however, whether the contractile 

 power of the Duct itself does not afford important aid in the process ; and it is 

 easy to understand, from the known influence of the Sympathetic system of 

 nerves upon it ( 654), that peristaltic movements may be excited at the time 

 when they are needed. It is an interesting fact, proving how completely the 

 passage of Bile into the Intestine is dependent upon the presence of aliment 

 in the latter, that the Gall-bladder is almost invariably found turgid in persons 

 who have died of starvation ; the secretion formed at the ordinary slow rate 

 having gradually accumulated for want of demand. This fact is important in 

 juridical inquiries. 



664. Of the operation of the Bile in the Digestive process, enough has 

 already been said ( 446). No certain information has yet been obtained, 

 whether any of the elements of the Bile itself are absorbed in the form of 

 Chyle ; or whether the Bile acts simply as a precipitant, and is altogether 

 cast out of the system, with the useless portion of the chyme. There can be 

 no question, however, that by far the largest part of the secretion is destined 

 to be entirely thrown off; and it would seem, from the character of its proxi- 

 mate elements, as if it were intended to remove from the Blood its superfluous 

 Hydro-Carbon, whether this have been absorbed as such from the aliment, 

 or have been taken up by the Blood as effete matter, during the course of the 

 circulation. If more non-azotized food be taken into the system than can 

 be got rid of by the Respiratory process, and if there is not a sufficiently rapid 

 production of Adipose tissue to admit of its being deposited as Fat, it would 

 accumulate in the Blood, unless separated by the Liver. If too much work 

 be thrown upon this organ, its function becomes disordered, from its inability 

 to separate from the Blood all that it should draw off: the injurious substances 

 accumulate in the Blood, therefore, producing various symptoms that are 

 known under the general term of bilious. This is particularly liable to happen 

 in warm climates, in consequence of the diminished excretion through the 

 Lungs, occasioned by the warmth of the surrounding air, and the small 

 quantity of exercise usually taken. To remove these symptoms, medicines 

 are required, which shall stimulate the Liver to increased action. The con- 

 stant use of such, however, has a very pernicious effect upon the constitution ; 

 and careful attention to the regulation of the diet, especially the avoidance 

 of a superfluity of oily or farinaceous matter, together with the employment 

 of an increased amount of exercise, will probably answer the same end in a 

 much better manner. Besides the source of Biliary matter already pointed 

 out, in the decomposition of the Fibrinous tissues ( 648), it seems probable 

 that there is another very important one in the continual waste of Nervous 

 matter, which nearly approaches bile in composition ( 643) ; especially if, as 

 asserted by Fremy, the peculiar acids of the Brain may be detected in the 

 Liver. In cases of slow Asphyxia, the amount of the Biliary secretion is 

 much increased. 



665. It would not seem improbable, that the Liver acts towards the absorbed 

 matters which enter the blood by the Mesenteric Veins, the same part which 



