78 PRACTICAL HISTOLOGY. 



old method of placing in ether for twenty-four hours a piece of adipose 

 tissue from an animal just killed. The fat is thus abstracted more or 

 less completely from some of the cells, and the collapsed membranes 

 are rendered visible. Perhaps the best method, however, is the 

 following : Digest a piece of skin as described in 223, b ; make 

 vertical sections, stain with carmine, and preserve in glycerine. In 

 many of the fat cells there is a wide space between the fat and the 

 envelope, and the stained nucleus is readily seen on the interior of the 

 latter. 



IOQA. Examine a preparation of fat cells showing crystals 

 of margarine. These sometimes appear after death. They 

 are almost always to be found in fat taken from an animal 

 recently killed, and mounted for some time in glycerine. 

 They are also often found in the fat cells of organs, e.g., 

 skin hardened in chromic acid and mounted in glycerine. 



no. Adenoid Tissue (H.) With the aid of the 

 freezing microtome make an extremely thin section of a 

 fresh mesenteric gland of a fasting animal recently killed. 

 Detach the lymph corpuscles from the adenoid tissue by 

 gently shaking the slice in a test-tube with J per cent salt 

 solution ; mount the section in Farrants' solution, and 

 examine. 



Adenoid tissue consists of a reticulum of nucleated 

 connective tissue corpuscles, the processes of which have 

 been transformed into fibres. Lymph corpuscles will be 

 found in the interspaces. (This section will be wanted on a 

 future day.) 



in. Examine a section of a lymph gland prepared as 

 follows : Into the mesenteric gland of a fasting cat or dog 

 recently killed, thrust the nozzle of a Wood's syringe through 

 the capsule of the gland, and inject per cent silver nitrate 

 solution. Make sections with the freezing microtome, wash 

 away the superfluous silver with distilled water, expose in 

 the water to diffuse daylight for a few hours, stain with 

 logwood. The adenoid tissue is coloured brown, while the 

 lymph corpuscles are rendered violet. The latter may be 

 detached by shaking in a test-tube with ordinary water. 

 The sections may be preserved in Farrants' solution, or in 

 glycerine, or glycerine jelly. 



Other preparations of adenoid tissue will be obtained 



