276 Royal Society. 



and at last ceases to exist, and the epithelial particles no longer 

 retain their individuality, but appear to be reduced to mere nuclei, 

 set very close together in a faintly granular basis substance. The 

 mode of their termination is not uniformly the same; frequently they 

 present distinctly closed rounded extremities, between one and two 

 thousandths of an inch in diameter; at other times they seem to 

 cease gradually in the midst of fibrous tissue, the nuclei alone being 

 disposed for some little way in such a manner as to convey the idea 

 of a continuation of the duct. These ducts can seldom be dis- 

 cerned in the fissures, but have several times been seen in the 

 " spaces," where several fissures unite ; they do not form anything 

 like a plexus between the lobules. From the anatomical relation of 

 the duces to the parenchyma, and from the circumstance that a 

 distinct vessel conveying a different kind of blood is distributed to 

 the hepatic duct, as soon as the liver assumes the parenchymal form, 

 it seems probable that the mode in which the secreted bile is con- 

 veyed out of the organ, is by its permeating the coats of the minute 

 ducts in obedience to an endosmotic attraction, which takes place 

 between the bile in which the ducts may be said to be bathed, and 

 a denser (perhaps mucous) fluid formed in their interior. The 

 large quantity of oily matter frequently existing in a free state in 

 the secreting parenchyma of the liver, which must be regarded as a 

 product of secretory action, seems to suggest the idea, that a cer- 

 tain quantity of the biliary secretion may be directly absorbed into 

 the blood, and in this manner conveyed away from the organs, just 

 as occurs in the thyroid body, suprarenal capsules, and other 

 glands unprovided with efferent ducts. 



With respect to the development of the liver, the author considers 

 the opinion of Reichart to be decidedly the correct one, namely, 

 that its formation commences by a cellular growth from the germi- 

 nal membrane, independently of any protrusion of the intestinal 

 canal. On the morning of the fifth day, the oesophagus and stomach 

 are clearly discernible, the liver lying between the heart, which is in 

 front, and the stomach which is behind ; it is manifestly a parenchy- 

 mal mass, and its border is quite distinct and separate from the digest- 

 ive canal ; at this period, the vitelline duct is wide, it does not open 

 into the abdominal cavity, but its canal is continued into an anterior 

 and posterior division, which are tubes of homogeneous membrane, 

 filled, like the duct, with opaque oily contents ; the anterior one 

 runs forwards, and forms behind the liver a terminal expanded 

 cavity, from which then passes one offset, which, gradually dilating, 

 opens into the stomach ; a second, which runs in a direction up- 

 wards and backwards, and forms apparently a caecal prolongation ; 

 and a third and fourth, which are of smaller size, arise from the 

 anterior part of the cavity and run to the liver, though they cannot 

 be seen to ramify in its substance ; at a somewhat later period, these 

 offsets waste away, excepting the one which is continued into the 

 stomach, and then the mass of the liver is completely free and un- 

 connected with any part of the intestine. As the vitelline duct 

 contracts, the anterior and posterior prolongations of it become 



