1894.] MICROSCOPICAL JOURNAL. 67 



tery," from the aorta and the " portal vein," from the 

 capiUary system of the intestinal tract and the hepatic 

 vein leaving- on the anterior side. The vessels as they en- 

 ter the organ begin to divide into lesser and lesser ves- 

 sels, and this g-oes on till they are ultimately minute "ar- 

 terioles," such as is seen in Fig. 5, in the portal canal, 

 also this is one of the vessels seen at P. en. in Fig. 1. 

 These vessels of the aortic and portal sources at the time 

 they are ready to pass into cajtillaries are found in the 

 areas between the "lobules," which compose the substance 

 of the liver. In Fig. 1, a view of the appearance of a 

 section only slightly magnified is presented. As the ac- 

 companying scale shows, the enlargement is here only 

 about eighteen diameters. In such a view as this a sec- 

 tion will appear to be made up, indistinctly, of hexago- 

 nal portions each with a hole in the centre and here and 

 there between the hexagons a vascular-looking passage 

 will be seen. Subsequent study with the higher powder 

 will prove that these areas are the cellular tissue of the 

 organ and the fact that sections in any plane will give 

 the same appearance, prove that the organ is composed of 

 polygonal blocks, each one a system of cells with an ar- 

 rangement like that of all the other blocks. The central 

 hole is called the " intra-lobular vein." By applying the 

 scale to the measurement of a single lobule it is found to 

 be about three one hundredths of an inch in diameter. 

 We thus learn that the coarse anatomy of the cat's liver 

 is a great number of masses called lobules, each one about 

 a thirtieth of an inch in greatest diameter, that these are 

 supplied with blood from the aorta and from the portal 

 vein, that the organ is drained by the hepatic A^ein which 

 flows off into the right side of the heart, that the secre- 

 tion of the organ is drained out into the small intestine. 

 Cellular Structure of the Liver. — To follow out 

 the distribution of the blood vessels an injected specimen 

 is needed. Injected specimens that are sold by the deal- 



