Anatomy and Physiology, 65 



the tube has been taken by Karsten and by Nicolucci for a 

 peripheral blood vessel, while the little drops of the white 

 amorphous substance figure in Meckel as hepatic cellules. 

 The parenchyma is quite distinguished from blood vessels by 

 the cellules of which it is composed, while in every blood 

 vessel we find true blood-globules. We sometimes find by 

 the side of the tube a line (trainee) of cellular tissue, on which 

 a few hepatic cellules of a torn tube are accidentally placed, 

 at other times the latter are to be found on a line of coagul- 

 able substance. These different lines have been taken by 

 Karsten for the peripheral blood vessels detached. Nowhere 

 have we been able to discover the trace of a blood vessel on 

 the tube. By compression it is emptied, and folds are then 

 apparent. We have sometimes found at the extremity of a 

 tube some transverse fibres. It is probably these fibres or 

 the folds that have been taken by Karsten for peripheral 

 vessels. Nicolucci declares as such the intervals between 

 the little drops of the white amorphous substance, which he 

 takes j as we have already said, for hepatic cellules. 



The facts which we have just cited, prove evidently that the 

 hepatic cellules in the crustaceae do not detach themselves to 

 be carried along in the bile, as is the case with the cellules of 

 other glands. M. Tereboullet first advanced the opinion that 

 in the cloportides the cellules of the liver are carried into the 

 interior of the alimentary canal : but I immediately combated 

 this view, and it seems to have been given up by its author. 



What reason is there to prevent the hepatic cellules in the 

 crustaceae from falling into the biliary canal ? It is the 

 presence of a special membrane which bounds this canal, of 

 which we have formerly announced the existence, and which 

 has been also seen by Meckel and Karsten. 



The researches of which we have just been speaking are very 

 delicate and difficult to make : but these difficulties are further 

 augmented when we have to deal with the livers of the higher 

 animals, and especially of the vertebratae. Does then a dis- 



