STEUCTUBE OF GLANDS. 



255 



attached to the enlarged excretory duct, these, in their turn, 

 having still smaller, rounded blind cells (fig. 255, B) sur- 

 rounded by vascular net-works attached to them, an arrange- 

 ment by which the whole structure acquires a cauliflower 

 appearance. The Cowper's glands of the hedgehog, on the 

 other hand (fig. 256, A), afford an example of that form in 

 which the ramified excretory duct divides into elongated, 

 pretty even, and slender cocca, which subdivide at their ends 

 into finger-shaped processes (fig. 256, B), partly straight, 

 partly sinuous, which are then applied to one another in the 

 form of flat lobules, these, in their turn, being connected by 

 cellular tissue into larger lobes. 



[ 421. In B 



man and the 

 higher verte- 

 brata, glands of 

 the simple fol- 

 licular form (as 

 they exist in the 

 Lieberkiihnian 

 glands of the 

 intestines, for 

 example) attain 

 to the highest 

 degree of com- 

 plexity in the 

 liver, for in- 

 stance. The com- 

 pound glands 



may be arranged according to their structure into four 

 groups. 1. Compound follicles, the short excretory canal 

 passing without farther ramification at once into pedicu- 

 lated vesicles or racemiform lobules ; or the outwardly simple 

 sac exhibiting internally open cellular projections or shallow 

 pits ; to this head belong the greater number of the larger 

 mucous and cutaneous glands. 2. Glands with tree-like 

 ramifications of their excretory duct, and enlargements of the 

 terminal branches into racemiform or cauliflower-like aggre- 

 gated vesicles, which are visible with the naked eye, and vary 

 in magnitude from the 25th of a line to one line. To this 

 group belong the lachrymal glands, the salivary glands, and 



Fig. 256. A, the Cowper's gland of the hedge- 

 hog, with the excretory duct, a. The coeca composing 

 the gland are filled in the most beautiful manner 

 with the mercury ; the object is not magnified. B, 

 a few of the blind sacs seen slightly magnified. 



