PERSPIRATION. 135 



indeed, of a simple tube, presenting a coiled mass beneath 

 the skin, the sudoriparous portion, and a tube of greater 

 or less length, in proportion to the thickness of the cuta- 

 neous layers, which is the excretory duct, or the sudoriferous 

 portion. 



The glandular coils vary in size from y^ to -~ of an inch ; 

 the smallest coils being found beneath the skin of the penis, 

 the scrotum, the eyelids, the nose, and the convex surface of 

 the concha of the ear, and the largest on the areola of the 

 nipple and the perineum. Yery large glands are found 

 mixed with smaller ones in the axilla, but these produce a 

 peculiar secretion which will be specially considered. The 

 coiled portion of the tube is about -g-fg- of an inch in diame- 

 ter, and forms from six to twelve convolutions. It consists 

 of a sharply defined, strong, external membrane, from -^^ 

 to g-J^. of an inch in thickness, very transparent, uniformly 

 granular, and sometimes indistinctly striated. This is of uni- 

 form diameter throughout the coil, and terminates in a very 

 slightly dilated, rounded, blind extremity. It is filled with 

 epithelium in the form of finely granular matter, usually not 

 segmented into cells, and provided with small oval nuclei. 

 The glandular mass is surrounded with a plexus of capillary 

 blood-vessels, which send a few small branches between the 

 convolutions of the coil. Sometimes the coil is enclosed in 

 a delicate fibrous envelope. 



The excretory duct is simply a continuation of the glan- 

 dular coil. Its course through the layers of the true skin is 

 nearly straight. It then passes into the epidermis between 

 the papillae of the corium, and presents, in this layer, a num- 

 ber of spiral turns. The spirals vary in number according 

 to the thickness of the epidermis. Sappey has found from 

 six to ten in the palms of the hands, and from twelve to fif- 

 teen in the soles of the feet. As it emerges from the glandu- 

 lar coil, the excretory duct is somewhat narrower than the 

 tube in the secreting portion ; but as it passes through the 

 epidermis, it again becomes larger. It possesses the same 



