Endothelium. 65 



The ciliated cells will be found isolated and can be 

 readily examined. Two other varieties of cells will be 

 found, which are the cells of the deeper layers and they 

 are not ciliated ; try with the J to make out the stria- 

 tion of the line running across the cell at the base of 

 the cilia ; a good glass will show this ; the T ^ oil im- 

 mersion will show that this striation is caused by the 

 cilia, which are continuous with the longitudinal stria- 

 tion in the body of the cell. 



Make a transverse section of the epididymis of man 

 or dog prepared in chromic acid mixture and stained 

 with logwood. Here the ciliated cells will be beauti- 

 fully shown, the cilia being much longer than in the 

 trachea ; they can be traced through the striated 

 border, with a high power in the same manner, as in 

 the cells of the trachea. 



ENDOTHELIUM. 



Take a portion of mesentery of cat and prepare by 

 the silver process. When it has been left long enough 

 in distilled water, stain it with logwood and mount in 

 glycerine ; seal and examine. 



The nuclei will be well shown by the logwood stain, 

 but the outlines of the cells will not probably be very 

 distinct at first, but will become more so by the action 

 of light. It will then be seen that the silver has been 

 deposited in the intercellular substance between each 

 cell, giving it a dark border. By focussing carefully a 

 second layer of cells will be brought into view, whose 

 outlines do not correspond with the first ; these are the 

 endothelial cells on the other surface of the membrane. 



