X] CONNECTIVE TISSUE 77 



processes. In some places the pigmented cells will 

 appear as round dots, the processes in this case having 

 been retracted. Every intermediate stage between 

 these two states may be observed by watching from 

 time to time. 



Cut off the foot, and pin out on cork the web 

 between two of the toes. Pour a little 95 p.c. alcohol 

 on the foot. In about 5 minutes cut out the web, and 

 put it in 95 p.c. alcohol in a watch-glass. In a quarter 

 of an hour transfer to fresh 95 p.c. alcohol for another 

 quarter of an hour. Then remove excess of alcohol by 

 pressing the web for a moment with dry blotting-paper, 

 and place in oil of cloves. When the web is transparent, 

 mount in balsam ; and examine again the pigment- 

 cells. 



Pigment-cells will be seen later in preparations of 

 the mesentery, and of the lymphatica cisterna magna 

 (Lesson xvm. 1, 2). 



16. Fat-cells. Cut out a small piece of the 

 omen turn, from a part containing comparatively little 

 fat. Spread it out on a slide and mount it in normal 

 saline solution. Observe 



a. Under a low power, the groups of highly re- 

 fractive fat-cells. 



b. Under a high power, the variable size of the 

 fat-cells, the apparent absence of a nucleus, the con- 

 nective tissue passing between and over the cells. 



17. Place a similar piece of omentum in osmic acid 

 *5 p.c. for about half-an-hour, wash with water, cut in 

 half, mount one half at once in dilute glycerine, and 



