70 



LABORATORY METHODS OP 



phafic g-lands. Sometimes the cells do not adjust 

 themselves completely, and a space is left, called pseu- 

 do-stomata. The pleura, pericardium and peritoneum 

 are serous membranes. The serous membranes are 

 not in contact with the air. 



THE MUCOUS MEMBRANES. 



This variety of tissue is in such a position that it 

 may come in contact with the air. It is composed of 

 the following structures : epithelial cells, basement 



DIAGRAM OF THE DIFFERENT TYPES OF GLANDS. 



1, Simple tube; 2, compound tube; 3, simple coiled tube; 



4, compound saccular; 5, simple saccular, 



