HISTOLOGICAL DEMONSTRATIONS. 119 



Mount an unstained section of liver in Farrants* solu- 

 tion, and compare it with the preceding. 



202. Blood-vessels (L.) Section of liver of cat, injected 

 from the portal vein with Prussian blue and gelatine, and 

 hardened in rectified spirit. Mount in dammar, and examine. 

 The radicles of the hepatic vein lie in the centre, the ter- 

 minations of the portal vein between the lobules and capil- 

 laries connect the two venous systems. 



203. Bile ducts (H.) Examine a section of rabbit's 

 liver having the bile ducts injected with soluble Prussian 

 blue ( 346), and the venous system injected with carmine 

 and gelatine, mounted in dammar. The larger (inter- 

 lobular) bile ducts are filled with injection, around which 

 the columnar epithelium may be seen. Lateral branches 

 may be readily traced into the lobules. The columnar epi- 

 thelium becomes shorter and shorter, and soon disappears. 

 The branches ramify, and soon open into a network of fine 

 ducts the bile capillaries between the individual hepatic 

 cells. These capillaries appear to be mere rounded spaces 

 between the cells. If, after having seen this injection, the 

 student carefully look with H. at the uninjected preparation 

 already made ( 200), he may see here and there fine pores 

 between the cells the empty bile capillaries much smaller 

 than the spaces that contain the blood capillaries. 



204. Glands of the Bile Ducts. The large bile ducts 

 have numerous mucous glands which may be seen in T. S. 

 of the duct, most readily after they have been filled with 

 injection from the common bile duct. Examine (L.) a 

 preparation showing these. 



SALIVARY GLANDS AND PANCREAS". 



205. Methods. a. These organs if cut into sufficiently small 

 pieces may be well hardened in a saturated solution of picric acid, as 

 recommended by Ranvier. About forty-eight hours are required. 

 Sections may then be readily made with the freezing microtome. They 

 may be mounted unstained in Farrants' solution, or in glycerine ; or 

 they may be stained with picro-carmine, and mounted in the same 

 fluids. 



b. The glands may also be hardened in alcohol, and sections made 

 with the hand. The sections may be stained with Beale's carmine fluid 

 ( 318, a), diluted four or five times with water. 



