4 CHAPTER III. 



THE SIMPLE TISSUES. 



The methods of preparation are indicated by the following abbrevia- 

 tions : p. = Preparation, s. = Stain, c. = Method of cutting, G. = Gum, 

 P. = Paraffin. C. Celloidin. m. = Mounting fluid to be employed, 

 B. = Canada balsam, F. = Farrant, Gl. = Glycerin. The numbers refer 

 to paragraphs in the appendix. 



Endothelium. Omentum of a guinea piy. 



Treated with nitrate of silver. The piece of tissue in alcohol is 

 placed in water. Mount it in balsam. There are thicker portions 

 in which blood-vessels run. Cut away the thickest parts by pressing 

 the edge of a knife where you wish to sever the tissue. 



(//} Find on the more delicate fenestrated omental tissue 

 the blackened outlines of the endothelial cells, due to the action 

 of the silver salt. The cells adapt themselves closely to the 

 surfaces which they cover. On the non-fenestrated portions of 

 the membrane single cells or small clusters of three or four 

 cells more deeply stained than the rest are met with (germinal 

 cells). 



Stratified Squamous Epithelium. Detached cells from 

 the human mouth. 



With your finger remove some saliva from the inside of your 

 cheek, mount between glasses. 



Search (H) for large irregular cells. Their surfaces exhibit 

 slight ridges, and each has a nucleus surrounded by fine 

 granules. The surface of the cells is frequently covered with 

 coarse granules (micrococci). To render the nucleus more 

 evident, stain with magenta or Spiller's purple by irrigation. 

 Watch the staining taking place under a low power, and 



