CUTANEOUS AND MUCOUS FOLLICLES. 



555 



Fig. 167. 





each of which it is provided with special 

 organs. Of these the most important is the 

 Perspiration ; which is formed in small 

 glandular organs seated just beneath the 

 cutis, and diffused over the whole surface of 

 the body. The efferent ducts of these 

 Glandulse open by minute pores in the 

 Epidermis, which are seen in elevated lines 

 on the skin of the palm of the hand and 

 the sole of the foot ; they penetrate the 

 epidermis rather obliquely, so that a sort 

 of little valve is formed by it, which is lifted 

 up by the excreted fluid as it issues. The 

 ducts pass through the Epidermis and Cutis 

 in a spiral direction ; and then enter the 

 glands, which consist of the convolutions of 

 the ducts, more or less subdivided, on which 

 blood-vessels are distributed. Where the 

 Epidermis is thin, the canal is straighter. 



700. The Secretion of fluid by these 

 Glands is continually taking place ; but this 

 fluid, being usually carried off in the form 

 of vapour as fast as it is separated, does not 

 accumulate and become sensible. If, how- 

 ever, from the increased amount of the se- 

 cretion, or from the condition of the sur- 

 rounding air, the whole fluid thus poured 

 out should not evaporate, it accumulates in 

 minute drops upon the surface of the skin. 

 Thus the Sudoriferous excretion may take 

 the form either of sensible or insensible 

 transpiration ; the latter being constant, the 

 former occasional. It is difficult to obtain 

 enough of this secretion for analysis, free 

 from the sebaceous and other matters which 

 accumulate on the surface of the skin; and 

 its character can only, therefore, be stated 

 approximately. It has usually an acid re- 

 action, which seems due to the presence of 

 lactic acid ; and to this we are probably to 

 attribute the sour smell which it has, espe- 

 cially in some disordered states of the sys- 

 tem. The proportion of solid matter was 

 considered by Renard to be about l-10th ; 

 but according to Anselmino it varies be- 

 tween 5 and H per cent. The greatest 

 part of it consists of animal matter, which is apparently a protein-compound 

 in a state of incipient decomposition. The remainder consists of saline com- 

 pounds ; of which the chlorides of potassium and sodium appear to be pretty 

 constantly present ; whilst the muriate of ammonia, free acetic acid, and 

 acetate of soda, have also been said to occur in it.~ The proportion of these 

 ingredients would probably be found larger in the fluid of the Sudoriferous 

 glands, if we had the means of collecting it separately ; for of the whole fluid 

 which passes off from the surface of the Skin, only a small proportion can be 

 properly said to be secreted by the Sudoriferous glands ; the greater part, 



Sudoriferous Gland from the palm of the 

 hand, magnified 40 diameters; 1 , 1, contorted 

 l ubes, composing the gland, and uniting into 

 two excretpry. ducts, 2, 2, which unite into 

 one spiral canal, that perforate^ the epider- 

 mis at 3, and opens on its Surface at 4; the 

 gland is imbedded in fat-vesiclea, which are 

 seen at 5, 5. (After Wagner.) 



