264 DIGESTION. [CHAP. xxv. 



vessels, while from the residuum the bile is formed, which is con- 

 veyed away by the biliary ducts/' 



During the latter days of incubation of the hen's egg, the liver 

 assumes a completely yellow colour, instead of the reddish-brown 

 which it had previously. This is connected with the rapid ab- 

 sorption of the yolk, probably by the blood-vessels of the yolk-sac, 

 which carry it to the liver, where it finds its way from the blood- 

 vessels into the fine gall- ducts, which at this time are full of 

 particles exactly the same as the yolk-globules. These particles 

 are not carried into the intestine along the biliary passages, but 

 undergo a change by which, on the one hand, blood- corpuscles are 

 formed and pass into the blood-vessels, and on the other hand, 

 bile is generated and carried off by the ducts. 



Weber states that he has observed a similar phenomenon in the 

 liver of the frog in the spring of the year, when the sexual organs 

 are highly developed, and when the lymphatic system is in a highly 

 active state. The liver undergoes a change of colour from reddish- 

 brown to a greenish-yellow. It is covered with dark pigment-cells, 

 and contains numerous opaque masses, which probably consist of 

 the colouring-matter of the bile, which may have accumulated 

 during the winter, but which now undergo gradual solution and 

 pass off in the bile. The peculiar colour which characterizes the 

 liver at this time, in the frog, is resident, as with the chick, neither 

 in the blood-vessels nor in the hepatic cells, but in the minute 

 ramifications of the gall-ducts, which are filled with numerous 

 small globules containing fatty particles. These undergo the same 

 metamorphoses as those of the chick into blood -corpuscles. 



This highly interesting subject requires further investigation to 

 ascertain whether similar phenomena may be noticed in other 

 animals, as in intra-uterine life in Mammalia or in hybernating 

 animals or whether, indeed, they may not be constantly occurring 

 in adult animals, although with less activity than in the young. 



The question occurs to us, may the liver be a source of supply 

 of blood-corpuscles, or may it contribute to the production of 

 hsematine in adult life ? It has often struck us that this question 

 might be answered in the affirmative, while observing cases in which 

 the process of the formation of blood seemed greatly perverted, 

 where no organic disease could be detected beyond some degree of 

 enlargement of the liver. Patients suffering in this way are pale, 

 as if from loss of blood, although no such loss had been ex- 

 perienced; their nutrition is enfeebled, digestion impaired, and 

 there is slight yellowness of the complexion, as in cases of hepatic 



