— 26 — 



(d) Fat Cells. 



Tlie meseiitoiy of n cat was spread on a lary;e glass sliile, 

 ■liardenetl for 48 liours iu 95% alcohol, stained in liannatoxylin, 

 washed in water, dehydrated, and cleared in oil of bergamot. A 

 small portion inclnding an arteriole is cut off with scissors, trans- 

 ferred to the slide, and mounted in balsam. 



Study first under low power, and observe the large, 

 clear, round or oval, cells, arranged in rows or small groups 

 on eitlier side of tlie small vessels. Under high power a 

 nucleus is now and then made out. A network of capil- 

 laries embracing the fat cells is often observed. Sketch as 

 seen under low i)Ower. 



(e) Section of Adipose Tissue. 



A small portion of the skin was hardened in absolute alcohol, 

 stained in })onix carmine, embedded in paraffin, and sectioned. 

 Fix to the sli<le and mount. 



Study under low ])ower. Notice the groups of fat cells, 

 lobules of fat, separated by bundles of fibrous connective 

 tissue. Sketch' as seen under low power. 



(f) Endothelial Cells. 



A 1% solution of silver nitrate was injected into the peritoneal 

 cavity of a frog. After 15 minutes the intestines witli the attached 

 mesentery were removed, pinned out on a small piece of cork, placed 

 into ^0% alcohol, and exposed to the sunlight until it assumed a 

 brown color. After dehydration the tissue was cleared in oil of 

 bergamot. jNIount in balsam. 



Study under high power, and observe that the silver is 

 deposited in the intercellular cement substance, a delicate 

 black line surrounding and outlining each cell. Now and 

 then the })rotoplasm and nuclei are stained a light Ijrown. 

 Sketch as seen under high power. 



