224 PRACTICAL HISTOLOGY. 



lymphatics. Other lymphatics accompany the 

 branches of the hepatic veins, but are not so easily 

 seen in the sections, although they can be injected. 

 The branches of the hepatic veins are readily dis- 

 tinguished from those of the portal vein, by the fact 

 that they run unaccompanied by branches of the bile 

 duct and hepatic artery. The blood capillaries of 

 the lobules look like spaces (tilled with round clear 

 bodies, the altered blood corpuscles) between the 

 rows of cells (in the sections these appear arranged 

 simply in rows) ; their walls are very thin, and the 

 hepatic cells appear for the most part to come in 

 contact with the wall. But in reality there is a 

 second delicate membrane around many of the capil- 

 laries, and between it and the epithelioid wall of the 

 vessel is a space for the passage of lymph (perivascu- 

 lar lymphatic) ; it is difficult to make this out, how- 

 ever, in preparations in which the lymphatics are 

 not injected. The round nuclei of the liver cells are 

 deeply stained by the logwood, and the cells them- 

 selves slightly. In the thinnest parts of the sections 

 the lines of junction between neighboring cells can 

 be well made out, and not unfrequently the small 

 capillary passage for the bile which intervenes be- 

 tween the adjacent sides of the cells can, according 

 to the direction in which it runs, be recognized with 

 a very high power either as a horizontal line or as a 

 minute aperture. To obtain the best results the 

 pieces of liver, which are not to be more than an 

 inch or so square and a quarter of an inch thick, 

 should be placed in the bichromate solution quite 

 fresh, from an animal killed only a short time pre- 

 viously. 



Preparation 2. Injected liver. The vessels 

 of the liver seldom get tilled when the rest of the 

 body is injected from the aorta. It is generally 

 necessary to make a special injection of this organ 

 from the portal vein. For this purpose the usual 

 red or blue gelatine injection is used, the apparatus 

 being arranged as described at p. 14t>. The operation 



