336 The Mickoscope. 



A COURSE IN ANIMAL HISTOLOGY. 



FRANK W, BROWN, M. D. 



FIFTH PAPER. 



A DIPOSE TISSUE.— (1.) Take a small piece of subcutaneous 

 "*■ -^ fat and tease out carefully in the salt solution. Cover and 

 examine with a low power. The fat vesicles will be seen arranged 

 in little groups or lobules. The lobules are separated from each 

 other by bands of connective tissue carrying blood vessels. Exam- 

 ining with a higher power, the connective tissue and vessels can be 

 traced into the lobules and between the vesicles. 



The vesicles are connective tissue corpuscles (plasma cells) 

 infiltrated with fat. Before deposition of the fat, they are flat, 

 irregular-shaped cells containing a nucleus and destitute of a 

 membrane. The fat is deposited first in a granular form. These 

 granules run together and form globules, which coalesce and 

 increase in size until the cell is completely filled. During this 

 process, a membrane is formed around the cell. The fat collects 

 within until the membrane is made tense, and the protoplasm and 

 nucleus of the cell are crowded to one side. Careful examination of 

 the edges of the vesicles will show the nucleus and protoplasm, 

 which appear as a thickening of the fibrous septa. 



(2.) Squeeze the specimen between cover and slide. On examin- 

 ation a few ruptured vesicles will be seen, showing the cell mem- 

 brane. 



(3.) Boil a small piece of adipose tissue in stronger alcohol for 

 five minutes, and then boil in ether for the same length of time.* 

 Mount in salt solution and examine. The fat having been removed 

 by the ether, exposes a good view of the cell membranes and fibrous 

 septa. 



(4.) Stain a piece of fat tissue in carmine, wash, dehydrate and 

 mount in balsam and examine. The balsam renders the fat trans- 

 parent, and the cell-body, with contained nucleus, deeply stained, 

 can be studied. A number of lymphoid (wandering) cells will also 

 be seen. The specimen can be preserved, if desired. 



(5.) Place a piece of omentum containing small groups of fat 

 lobules, in a one per cent, solution of osmie acid until it assumes a 

 brownish -black color. Mount in balsam and examine. The fat has 

 taken up the color, allowing a study of the contour of the vesicles 

 and their arrangfement in lobules. 



* Care should be taken when boiling in ether that the vapor be blown away as it 

 arises from the test tube, as it is inflammable and may ignite. 



