174 DETAILED SYNTHESIS. 



Glands are called simple or compound, according as they 

 are simple tubes, or branched (racemose) with clusters 

 of little pouches (cryptae or follicles) about them. 



120. THE CELLS OF ALL THE SURFACES and of the 

 Glands proper have beneath them a layer of basement 

 membrane, from the nuclei of which the cells take their 

 rise. 



121. THE MODE OF CELLULAR GROWTH AND ACTION 



is this : the cells take their origin from the nuclei of the 

 basement membrane, and enlarge to maturity, at the 

 same time filling themselves with their appropriate 

 secretion ; when mature, they are loosened from the 

 nuclear spot, and if at the surface, they break or dis- 

 solve away, yielding their contents to fulfil thfeir pur- 

 pose ; if not at the surface, they are crowded up by those 

 growing beneath them, and either dissolve, as in some 

 cases, or, drying, fall off as scales, as in case of the skin. 



122. THUS SUCCESSIVE CROPS OF CELLS ARE GROWING 

 in contact with the basement membrane, and successive- 

 ly wasting away in the very act of fulfilling their office. 



SECTION II. 

 Muscular Tissue. 



123. MUSCULAR TISSUE is another form of Secretory 

 Tissue, having- peculiarities very distinguishing. 



124. MUSCULAR TISSUE is IN THE FORM OF cells, the 

 walls of which are to appearance constituted of the same 

 albuminoid Elements as those of other kinds of cells ; 

 their contents have a jelly-like appearance. (See Fig. 78.) 



Remark. Muscular Tissue is sometimes described as composed of 

 tubes, as if the ends of the cells had broken down, allowing all in one 

 filament to form one continuous tube. 



125. THE MUSCULAR CELLS ARE PECULIAR in this, 

 that they have no relation to basement membrane for 

 their production. 



120. What beneath -? 121. What ? 122. What said -? 123. What f 

 124. What ? 125. How ? 



