228 



THE SKIX. 



muscular fibi-e-cells arranged longitudinally. In the larger glands, more- 

 over, the duct is rarely simple, being more usually parted by 



repeated dichotomous division 

 Fig- 157. into several branches, which 



before ending give off short 

 csecal processes ; in rare cases 

 the branches anastomose. On 

 carefully detaching the cuticle 

 from the true skin, after its 

 connection has been loosened 

 by putrefaction, it usually 

 happens that the cuticular 

 linings of the sweat-ducts get 

 separated from their interior 

 to a certain depth, and are 

 drawn out in form of short 

 threads attached to the under 

 surface of the epidermis. The 

 coils of the gland-tube are 

 loosely held together by con- 

 nective tissue (fig. 157), which 

 may form a sort of capsule 

 round the body of the gland. 

 Each little sweat-gland is sup- 

 plied with a dense cluster of capillary blood-vessels. 



Pig. 157 — Section of a Sweat-Gland. Highly 

 MAGNIFIED (Biesiadecki). 



The tubules are seen variously cut. a, base- 

 ment-membrane ; h, lining cells ; c, lumen of 

 tube ; d, blood-vessels and uniting connective 

 tissue. 



The contents of the smaller sweat-glands are fluid, without any formed elements ; 

 but in the larger sweat-glands of the axilla the contents are semi-fluid, and 

 abound in fine pale granules and nuclei ; or their secretion is extremely viscid, 

 with a varying quantity of large, opaque, colourless, or yellow granules, with 

 nuclei and cells, similar to epithelium-cells ; and in both cases it may also con- 

 tain fat. 



Distribution. — Sweat-glands exist in all regions of the skin, and attempts have 

 been made to detennine their relative amount in different parts, for they are not 

 equally abundant everywhere ; but, while it is easy to count their numbers in a 

 given space on the palm and sole, the numerical proportion assigned to them in 

 most other regions must be taken with considerable allowance. According to 

 Ki'ause, nearly 2800 open on a square inch of the palm of the hand, and somewhat 

 fewer on an equal extent of the sole of the foot. He assigns rather more than 

 half this number to a square inch on the back of the hand, and not quite so 

 many to an equal portion of sui-face on the forehead, and the front and sides of 

 the neck ; then come the breast, abdomen, and fore-ann, where he reckons about 

 1100 to the inch, and lastly, the lower limbs and the back part of the neck and 

 trunk, on which the number in the same space is not more than from 400 to COO. 



The size of the sweat-glands also varies. According to the observer last named, 

 the average diameter of the round-shaped ones is about one-sixth of a line ; but 

 in some parts they are larger than this — as. for example, in the groin, but 

 especially in the axilla. In this last situation Ki-ause found the greater number 

 to measure from one-thii'd of a line to a line, and some nearly two lines in 

 diameter. 



The development of the sweat-glands has been carefully studied by KoUiker. 

 Their rudiments, when first discoverable in the embryo, have much the same 

 appearance as those of the hairs, and, in like manner, consist of processes of the 

 mucous layer of the epidermis, which pass down and are received into corre- 

 sponding recesses of the corium. They are formed throughout of cells collected into 

 a solid mass of an elongated pyriform, or rather club shape, continuous by its small 

 end with the soft layer of tlie cuticle, and elsewhere sm-rounded by a homo- 



