The uses of the bile are threefold; 1. it acts chemically upon the chyme and produces the separation of the chyle ; 2. it combines with the residuum and forms the faecal matter ; 3. it stimulates the mucous surface of the canal and promotes its secretion, and the contractile action of the muscular coat.
Red and yellow substances of Ferrein. Since the period when anatomists were di vided in their considerations of the liver by the two great contending opinions of Malpighi and Ituysch, the former maintaining its com position of glands, and the latter of mi nute vessels, the majority of observers have adopted the views proposed by Ferrein, who was the first to vindicate the existence of two distinct substances, which he named cortical and medullary. It was reserved for Kiernan in our own day to prove that " the structure of all the lobules is similar;" that "each lo bule is the same throughout ; " that " one part of a lobule is not more vascular than another ;" and that " there is, therefore, no distinction of red and yellow substances in the liver ; the red colour results from congestion only." This doctrine being now established as an undis puted truth, it is not surprising to observe that anatomists and pathologists differed in opinion with regard to the relative position and appear ance which these two imaginary substances occupied in the respective livers which they chanced to examine, and upon which they established their decision. Thus we find that Ferrein described the medullary substance as being red in colour, and of a pulpy con sistence, and the cortical as friable in its struc ture, and of a yellowish red colour. Auten rieth, on the contrary, found the red substance to be cortical and the yellow medullary. Mappes having obtained a liver in a different state of congestion, conceives that the yellow substance might be named granulated; he de cribes it as forming convolutions, one while like intestines, and another while branched, flat, or rounded; and the spaces between the convolutions as being rounded, or resem bling oblong fissures filled with a brownish and loose substance. Meckel coincides with Mappes in the relative position of these parts ; they are not, he says, placed as in the brain, one on the exterior, the other in the interior, but they alternate throughout the entire organ, the yellow substance forming the mass of the liver, and the brown filling the interspaces. Rudolphi objects to the terms medullary and cortical. Bouillaud asserts that the yellow sub stance presents itself in the form of granu lations having the figure, colour, and arrange ment of the secreting granules of the bile known, as he remarks, under the name of acini. These granules, he says, are surrounded by the brown substance, which therefore as sumes an angular appearance; it is composed of a vascular net-work, and may be compared to erectile tissue. Andral, in his Anatomie Pathologique, says, "Lorsqu'on examine avec quelque soin un certain nombrg_sle foies, l'on y reconnitit l'existence de deux substances : Tune rougeatre, oil se ramifie surtout le sys teme capillaire de Forgone ; l'autre blanche ou jau nave, qui semble surtout destinee a t'accom plissement de la secretion biliare. Dans l'etat normal ces deux substances sont distinctes." The ()Onion of Ferrein is opposed by Portal and Cruveilhier : the former anatomist, after reproving certain modern authors who wished to combine the views of Malpighi and Ruysch by admitting that the liver was formed both of glands And of a prodigious number of vessels, contents himself by asserting that Ferrein's idea of the composition of the glands of the liver of two substances was gratuitous. To Cruveil hier the distinction of two substances appears ill founded, for he observes that the two colours when they exist, which is not constantly the case, do not belong to two distinct granula tions, but to one and the same, which is yel lowish in the centre where the bile predo minates, and of a brownish red in the circum ference where the blood is situated. Kiernan
ranks Muller among the authors who entertain an opposite opinion to that of Ferrein, but I find upon referring to his work upon the glands, that he distinctly admits a kind of double substance although he objects to its de signation, medullary and cortical ; hence he ob serves :—" Diversam substantiate hepatis, ut pote medullarem et corticalem, quw per hepar totum undique obveniunt, qualem Autenrieth, Bichat, Cloquet, Mappes, atque etiam J. Fr. Meckel admittunt, equidem neque in historic evolutionis amphibiorum et avium, neque in hepate adultorum microscopice observato con spexi. Ilistoria evolutionis hanc quiestionem evidentissime illustrat. Systema nimirum duc tuum biliferorum in embryone amphibiorum et avium liberis finibus in superficie hepatis pro minulis conspicuum. Sarmentula ilia foliatim et paUiculatim divaricata, colore e gilvo can dido nitent, magnopere ab interstitiis sanguino lentis distincta. Hine sane duplicis substantive species exoritur, quoniara circum ductuum bi liferornm a tela conjunctiva expleantur, Tree ex subtilissimis fere constat vascutorum sangui ferorum retibus, in quibus arterite et venulw advehentes in revehentes venas transeunt. Atque hive sola est utriusque substantive notio. Sed in omnibus organis glandulosis fere idem obvenit." In his Physiology he is disposed to modify his previous idea of two substances, for he says, " From my researches, however, it results that there is but one kind of real he patic substance, formed of agglomerated biliary canals ; but the ramified divisions of this sub tance being connected by a vascular cellular tissue, which is often of a dark colour, a con trast between this and the yellow substance of the acini is produced. A similar relation of the constituent parts of the liver exists in the embryo of the bird ; in it the yellowish twig like ramifications of the biliary canals are seen on the surface of the organ rising out of a reddish vascular tissue." M. Dujardin, in an article entitled, " Re cherches Anatomiqucs et 1\Iicroscopiques sue le Foie des Mammiferes,• has advanced some opinions which he conceives will throw a doubt over the labours of Kiernan. My space will not permit an analysis of his paper, but it will be obvious to all who may be disposed to read it, that he has not advanced a single new fact, but on the contrary has confessed the most imperfect and inadequate means of ex amination. Thus, he observes, " with an in jection sufficiently fine we can inject the portal vein as far as the capillaries which surround the lobules." Therefore, according to him, the interlobular veins are capillaries, and we need not wonder that with such injection he gets no further, but denies the existence of vessels in the lobules altogether. The lobules, he says, are composed of glutinous corpuscules or glo bules, which leave channels between them, through which the corpuscules of the blood pass without alteration ; at the same time by an action analogous to the phenomena of absorp tion and assimilation in the lower animals, these lobules separate from the serum the excre mentitious particles which are excreted upon the surface of the lobule. The blood of the portal vein is transmitted through the lobule by a kind of "filtration organique," and from it the resinous matters of the bile are elimi nated; the arteries, on the contrary, secrete the alkaline substances, which in the first instance dissolve the resinous substance, and afterwards constitute the true agents of digestion. M. Dujardin concludes his theoretical but inge nious speculations with an excuse for being obliged to give them to the world in their pre sent imperfect state, and promises to renew his researches with perseverance. I feel pleasure in recording his promise, and have no doubt that by better directed injections in the human liver, using size and vermilion in place of oils and varnish, he will be induced to modify his views with regard to this most interesting organ.