Mr. Beale on the Anatomy of the Liver of Vertebrate Animals. 471 



lobules. la most Mammalia, but not in the pig, a few of the finest 

 branches of tlie duct can be followed for some distance beneath the 

 surface of the lobule. These branches appear to lie amongst the 

 secreting cells, but are not connected with them. They become 

 continuous with tubes of the cell-containing network at a deeper 

 part, while those secreting tubes nearer the surface of the lobule are 

 connected with branches of the duct which do not penetrate. 



In many animals, particularly in the rabbit, and to a less extent 

 in man and in the dog, the smallest branches of the duct are con- 

 nected together so as to form a network, which is continuous with 

 that in which the secreting cells lie. 



In the pig, the small ducts are, as it were, applied to the surface 

 of the lobule ; from these smaller branches come off, which pene- 

 trate the lobule and are immediately connected with an intimate 

 network, which lies partly in the capsule of the lobule itself. This 

 network is continuous with, and may be looked upon as the most 

 superficial portion of, the cell-containing network. In a perfectly 

 normal state it contains only oil-globules and granular matter ; but 

 when the liver is fatty, it is found to contain liver-cells loaded with 

 oil. From such a liver the author has a very beautiful preparation, 

 in which the continuity of the very narrow duct with the wide tubes 

 of the network, distended with large cells containing oil, can be well 

 seen. The duct and the tubes in which the secreting cells lie, both 

 contain a little injection. 



The author has succeeded in demonstrating the communication 

 between the ducts and cell-containing network in several mamma- 

 lian animals, as well as in the human subject, by injecting the ducts 

 in the manner described. Of these, the seal, hedgehog, rabbit and 

 Guinea-pig have aflforded the best specimens. 



In Birds, the continuity in injected specimens has been traced in 

 the common fowl and in the turkey. The quantity of epithelium in 

 the ducts of birds forms a great obstacle to the passage of the injec- 

 tion, and from their extreme tenuity, the capillaries do not bear the 

 preliminary injection of much water. 



Reptiles. — The author has seen the continuity between the ducts 

 and cell-containing network, in an uninjected preparation of the 

 newt's liver, and in an injected liver of the adder. 



Fishes. — In consequence of the very fatty nature of the liver of 

 fishes, it was found to be very difficult to harden it sufficiently to 

 cut tliin sections. The frequent presence of entozoa and their ova, 

 renders it difficult to inject the ducts. The author succeeded in 

 injecting the ducts and part of the cell-containing network in the 

 sturgeon and in the Lophius, and in one instance, those of the very 

 fatty liver of the cod. The continuity was also traced in an unin- 

 jected liver of the common flounder. The injection often passes a 

 certain distance into the finer ducts of fishes, but cannot be forced 

 into tlie cell-containing network. In this way the appearance of 

 blind terminations to the ducts is produced, as tlie continuity of 

 the tube cannot be traced beyond the point at which the injection 

 stops. 



