1 68 PRACTICAL HISTOLOGY. [XII. 



reduce the silver. One piece may be mounted in balsam ; another piece should 

 be stained with acid logwood or picro-lithium carmine (in this case use dilute 

 hydrochloric acid), and mounted in balsam. 



(a.) Observe a large number of clear, branched anastomosing spaces, sur- 

 rounded by brown areas of ground-substance. The former are the cell-spaces 

 and Saft-Cancilchcn, or juice-canals, and some of the latter may be seen to 

 communicate with the lymphatics (fig. 136). 



(b.) In the stained specimen, stained nuclei are seen in the spaces, i.e. , the 

 nuclei of the cells which occupy these spaces. 



13. Cell-Spaces (Iron Sulphate Method}. Using the fresh central tendon of 

 the diaphragm of a mouse or guinea-pig or rat, place it for a few minutes in I per 

 cent, sulphate of iron. Pencil away the surface endothelium, and leave it in 

 the iron solution for five to seven minutes. Remove it, wash it, and place it 

 in i per cent, ferricyanide of potash, in which it becomes blue. Mount it in 

 Farrant's solution or balsam. In this preparation the cell-spaces and juice- 

 canals are again clear, but the ground-substance is blue. 



14. Cell-Spaces in Kat's Tendon. The fine tendons are placed in silver 

 nitrate (| per cent.) for two minutes, and then the epithelium is brushed off 

 by a camel's-hair pencil. Five or six sweeps of the brush usually suffice. The 

 tendons are stained for other ten minutes in silver, washed, and exposed to 

 light in alcohol. Rows of clear, somewhat quadrangular spaces in a brownish 

 matrix are obtained. 



LESSON XII. 



ADIPOSE, MUCOUS, AND ADENOID TISSUES- 

 PIGMENT CELLS. 



ADIPOSE TISSUE (FATTY TISSUE). 



Adipose Tissue. A fat-cell consists of a membrane enclosing a 

 globule of oil, which pushes the oval flattened nucleus (surrounded 

 by a small amount of protoplasm) to one side, so that it lies close 

 under the cell-wall. Size, 40 //, to 80 p (^-Q-^-Q inch). 



Fat-cells are arranged in groups, which form lobules, and these 

 again form lobes. Each lobule has an afferent artery, one or two 

 efferent veins, and a dense network of capillaries between the fat- 

 cells, each capillary surrounding one or more fat-cells. 



It is to be remembered that cells in connective tissue containing 

 fat may have a two-fold origin. Fat may be formed in ordinary 

 connective-tissue cells, but there are other cells of a connective- 

 tissue nature, which seem to be more specifically fat-cells. During 

 development this tissue is formed at certain parts, e.g., in the groin, 

 axilla, and neck, and presents a grayish-yellow appearance in the 

 form of lobules, surrounded by connective-tissue readily seen 

 in a young animal. The cells at first contain granules. The 



