THE LIVER. 685 



ing it was as follows: Pieces of the fresh liver best that of man or the 

 ox are frozen in a microtome and cut into thin sections. These are next 

 placed in a half per cent, solution of chloride of gold for thirty to forty 

 minutes. After this it is immediately washed carefully in distilled water, 

 and at once subjected to formic acid of a specific gravity of 112 from five to 

 eight minutes. The thinner the sections the less time is required for the acid 

 to act upon them. Immediately after their removal from the formic acid 

 they must be again thoroughly washed in distilled water and exposed to the 

 light, and then mounted in glycerine. 



The place most favorable for finding nerves is the porta. In the ox, in the 

 region where the large vessels enter the liver, there is considerable fibrous 

 connective tissue, in which numerous bundles of mostly non-medullated nerves 

 may be seen coursing in the interstices between the bundles. I have 

 succeeded best by taking sections from a portion of liver immediately border- 

 ing on the hepatic artery, a few inches from its entrance into the organ, or 

 some of its branches. I am also of the opinion that the best sections are made 

 by placing the material in the microtome in such a manner that the sections 

 are cut vertical to the artery. 



The nerves are marked by a large number of nuclei, by the presence of a 

 delicate sheath of perineurium around each fiber, and by the dark violet color 

 they had taken on from the treatment before described. 



On the border of the lobules the nerves, which were still in bundles of 

 from three to five, sometimes more, ramified and entered the lobules in dif- 

 ferent places, mostly branching at acute angles along the capillary blood- 

 vessels. As I have traced the nerves entering the lobule to their connection 

 with the bundles of nerves between the lobules, no doubt can arise as to the 

 nature of the fibers which I have seen. Such fibers are to be found in the 

 interlobular connective tissue distant from the porta, as well as in the con- 

 nective tissue of the porta itself. Unquestionably, therefore, the nerves pass 

 into the lobules and ramify along the capillary blood-vessels. This assertion 

 is based on the fact that the ramifying nerves were always seen running in 

 the light interstices between the liver epithelia, which, as we know, are 

 occupied by capillary blood-vessels only. 



The further course taken by the nerves can be understood only by consid- 

 ering the fact hitherto unknown to all observers namely, that the liver 

 epithelia are separated from each other by a delicate layer of cement-sub- 

 stance, in the same manner as all other epithelia and endothelia. The 

 significance of the thorns contained therein, according to the views of 

 C. Heitzmann, is plain. The reticulum in epithelia of all kinds was first 

 described by this observer in 1873, and it deserves mentioning that several 

 years later E. Klein, of London, claimed to be the first to describe the retic- 

 ular structure of the epithelia of the liver. Liver epithelia are in no way 

 different from other epithelia, and the reticulum has been proved by H. Chr. 

 Miiller to be composed of living matter, while Klein does not appear to have 

 any idea of its significance. The reticulum is connected in the center of the 

 epithelium with the wall of the nucleus, and at the periphery with those 

 filaments which penetrate the cement-substance, and interconnect all neigh- 

 boring epithelia. A light rim of this cement-substance is always present 

 between the endothelial wall of the capillaries and the adjacent wall of the 

 epithelium, and again this rim is traversed by delicate grayish filaments con- 



