IV.] 



EPITHELIUM AND ENDOTHELIUM. 



129 



Peritoneal Surface of the 

 Central Tendon of the 

 Diaphragm of a Rabbit. 

 Silvered. /. Lymphatic 

 slit ; t. Tendon ; c. Ordi- 

 nary endothelial cells ; n. 

 Islands of small cells. 



10. Endothelium of Central Tendon of Diaphragm. Mount 

 in balsam a small piece of the central tendon of the diaphragm of 

 a rabbit stained in silver nitrate (Method, 



P- 77). 



(.) Observe the polygonal areas which 

 map out the outlines of the single layer of 

 squames covering the surface of the tendon. 

 These areas are bounded by brown or black 

 lines, the so-called " silver lines " (fig. 89). 

 As a rule, no nucleus is visible in the cells, 

 but it may be brought into view by staining 

 with logwood and mounting the preparation 

 in Canada balsam. 



(b.) Amongst these may be seen small 

 groups or islands of smaller granular cells. 

 In some specimens stomata surrounded by 



granular or germinal cells may be seen. jio._8 9 . Endothelium of the 

 These stomata open into a plexus of lym- 

 phatic capillaries in the substance of the 

 tendon (Lesson on Lymphatics). 



11. Omentum of Young Rabbit (L and 

 H). Mount in balsam a small piece of the 



silvered omentum of a young rabbit (one week old) (Method, p. 77). 



(a.) Observe a thin fibrous membrane mapped into polygonal 

 areas some of them 

 with more or less 

 sinuous outlines by 

 means of black "silver 

 lines " (fig. 90). , 



The omental mem- 

 brane composed of 

 connective tissue is 

 covered on both sur- 

 faces with a continu- 

 ous layer of endo- 

 thclium. 



(/>.) Raise the lens 

 by means of the fine 

 adjustment until the 

 upper layer of squames 

 conies distinctly into 

 view ; then depress the 

 lens and focus through 

 the thickness of the. membrane to bring into view the. layer of 

 squames covering the deeper surface, and note that the outlines of 

 13 I 



FIG. QO. Omentum of a Young linhhit stained with Silver 

 Nitrate (x 300), showing the epithelium on the upper 

 and under surfaces ; the outlines of the latter faintly 

 indicated. Some holes are also seen in it. 



