170 DETAILED SYNTHESIS. 



SECTION I. 



Secretory Tissue. 



111. SECRETORY TISSUE MAY THEREFORE BE DEFIN- 

 ED as a homogeneous albuminoid substance or membrane, 

 compounded of the Elements of the first and second 

 groups, under the influence of secretory tissue previously 

 existing. 



112. VEGETABLE AND ANIMAL SECRETORY TISSUE 

 have the same general appearance and constitution. 



113. SECRETORY TISSUE EXHIBITS three general 

 forms : 1st, the extended or sheet-like, when it is called 

 basement membrane / 2d, the tubular / and 3d, the cellu- 

 lar. 



C Basement Membrane. 

 SECRETORY TISSUE -j Tubular. 

 ( Cellular. 



FIG. 123. 



Fig. 123 is a beautiful plan of cells, 1, resting on abasement membrane, 

 2, beneath which is the fibrous layer, 3, containing the blood tubes, 4, 

 The spot in the centre of the side of the cell is its nucleus. (For tubular 

 form of membrane, see i, Fig. 137.) 



114. THE CELLULAR FORM OF SECRETORY TISSUE 

 EXHIBITS numerous varieties, each of which changes its 

 form more or less, according to circumstances, such as 

 pressure, etc. Whether the form of the cells has any- 

 thing to do with the peculiar character of the secretion 

 formed by them, is not known ; it probably has, since 

 each different substance is secreted by a cell of a pecu- 

 liar form. 



115. THE MOST CONSPICUOUS CELLS ARE, 1st, the 



111 How ? 112. What said -? 118. What does -? Write table. Describe 

 Fig. 123. 114. What docs - ? 115. What ? 



