STYSANUS. 



[ 623 ] SUDORIPAROUS GLANDS. 



STYSANUS, Corda, = CEPHALOTRI- 



CHUM. 



SUCCINIC ACID. This acid, which 

 occurs in amber, in all fermented liquids, 

 and in the contents of Echinococcus cysts, is 

 pretty soluble in water, readily in hot but 

 with difficulty in cold alcohol, and but little 

 in aether. 



The crystals belong to the oblique pris- 

 matic system, and are represented in PI. 7 

 fig. 21. 



BIBL. That of CHEMISTRY. 



SUDORIPAROUS GLANDS. These 

 organs secrete the perspiration. 



Fig. 717. 



They are found in most parts of the skin, 

 but in variable numbers in different locali- 

 ties. Thus it has been estimated that 41 7 

 exist in a square inch of the skin of the back 

 of the hand, 1093 in an inch of the outside, 

 and 1123 in the inside of the fore-arm, and 

 2736 in an inch of the palm of the hand. 



Each gland consists of a long tube coiled 

 into a knot near the closed end, which is 

 situated in the subcutaneous cellular tissue, 

 and forms the gland proper, and a straight, 

 undulate, or spiral duct, which traverses the 

 skin perpendicularly, to terminate upon its 

 surface between the papillae. 



Fig. 718. 



Fig. 717. A sudoriparous gland, with its blood-vessels, a, proper gland ; b, duct ; c, blood-vessels of a gland. 

 Magnified 35 diameters. 



Fig. 718. Portion of the tube forming a sudoriparous gland from the hand, a, areolar coat; b, epithelium ; c, cavity. 

 Magnified 350 diameters. 



In the glands of the axilla, the portion 

 of the tube forming the gland proper is 

 branched, and sometimes the branches ana- 

 stomose. 



The coiled portion or proper gland is sur- 

 rounded and permeated by an elegant plexus 

 of capillaries; and some of them are sur- 

 rounded by a capsule of areolar tissue with 

 spindle-shaped cells. 



The tube of the glands exhibits two forms 

 of structure. In one of these there is an 

 outer coat of indistinctly fibrous areolar 

 tissue with elongated nuclei, sharply defined 

 internally by probably a basement mem- 

 brane, this being lined with one, two, or 

 more layers of polygonal pavement-epithelial 

 cells, mostly containing fat-globules and 

 pigment-granules. 



In the other form, the fibrillation of the 



areolar coat is tolerably distinct, the fibres 

 longitudinal, sometimes also with an inner 



Fig. 719. 



Portion of a tube with a muscular coat, from the scro- 

 tum, a, areolar tissue ; b, muscular layer ; c, epithelial 

 cells filling the tube, and containing yellow granules. 



Magnified 350 diameters. 



