422 T1IE SOLIDS. 



Development of the Liver. 



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

 the opinion of Ileichart to be decidedly the correct one, namely, that its 

 formation commences by a cellular growth from the germinal membrane, 

 independently of any protrusion of the intestinal canal. On the morn- 

 ing of the fifth day, the oesophagus and stomach are clearly discernible, 

 the liver lying between the heart which is in the front, and the stomach 

 which is behind ; it is manifestly a parenchymal mass, and its border is 

 quite distinct and separate from the digestive 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 upwards and backwards, and forms apparently a csecal prolon- 

 gation ; 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 unconnected with any 

 part of the intestine. As the vitelline duct contracts, the anterior and 

 posterior prolongations of it become fairly continuous and form a loop of 

 intestine, the posterior division being evidently destined to form the 

 cloaca and lower part of the canal. The final development of the hepatic 

 duct takes place about the ninth day, by a growth proceeding from the 

 liver itself, and consisting of exactly similar material; this growth ex- 

 tends towards the lower part of the loop of the duodenum, which is now 

 distinct, and appears to blend with the coats of the intestine ; around it, at 

 its lower part, the structure of the pancreas is seen to be in process of 

 formation. The further process of development of the hepatic duct will, 

 the author thinks, require to be carefully examined ; but the details he 

 has given in this paper have satisfied him of the correctness of the 

 statement that the structure of the liver is essentially parenchymal." 



PROSTATE GLAND. 



This gland belongs to the compound follicular division, and 

 not to the lobular class of glands ; its structure consisting of 

 clusters of follicles, united by ducts : these follicles are usually 

 of an oval form, of large size, and frequently communicate 

 with each other. 



* Dr. Hanfield Jones, Abstract of Paper in Philosophical Magazine, 

 September, 1847. 



