SECRETION. 



439 



found in connection with this tissue in most 

 parts of the body. Later researches have 

 shown a still further difference, viz. the pos- 

 session of another structure the unstriped 

 or organic muscular fibre which is either 

 not present in the subcutaneous textures of 

 other regions, or is in far more sparing quan- 

 tity. The contractility which is the function 

 of these fibres is quite independent of the will, 

 and is not only readily developed on the ap- 

 plication of a direct stimulus, but is also pro- 

 ducible by cold, and is associated with general 

 tonicity of the system. And in opposite con- 

 ditions of warmth or debility, a relaxation of 

 these fibres effaces the rugae which their con- 

 traction had previously produced. 



The vessels of the scrotum are numerous, 

 but of little surgical importance ; they are 

 derived from those of the thigh and perineum. 

 The superior and inferior external pudic, from 

 the femoral artery, terminate by sending many 

 small twigs to the integuments of the penis 

 and scrotum ; while, posteriorly, the internal 

 pudic of each side sends forwards a superficial 

 perineal branch, which likewise ends in these 

 tissues, by ramifying and anastomosing with 

 the preceding. The accompanying veins have 

 in all respects a corresponding distribution. 



The nerves are chiefly the anterior termi- 

 nations of those seen in the perineal space. 

 Thus on each side is the inferior pudenda!, 

 which leaves the sacral plexus with the small 

 sciatic nerve; while, nearer the median line, 

 are the two superficial perineal nerves (ex- 

 ternal and internal perineal). The branches 

 of these are very numerous, and are traceable 

 to the front of the scrotum. The 51io-in- 

 guinal, a small branch from the higher part of 

 the lumbar plexus, and which perforates the 

 abdominal muscles, together with a part of the 

 genito-crural nerve from the same source, 

 terminate near the front of the scrotum, but 

 extend very little on it. 



For the anatomy of the contents of the 

 scrotum, as well as its morbid appearances, the 

 reader is referred to the article " TESTICLE," 

 in which they will be included. 



( William Brinton.') 



SECRETION. This term is usually em- 

 ployed to designate the process of separation 

 of those matters from the nutritious fluids of 

 the body, which are destined, not to be 

 directly applied to the nutrition and reno- 

 vation of its organised fabric, but (1) to be 

 either at once removed as injurious to its 

 welfare, or (2) to be employed for some ul- 

 terior purpose in the chemical or physical pro- 

 cesses of the economy itself, or to exert some 

 kind of action upon other beings. The term 

 is often used, also, to designate the products 

 thus separated. 



The nature of this process of separation is 

 essentially the same in all cases, whatever 

 may be the destination of its products ; and 

 we shall consider it, therefore, in the first 

 place, without any further reference to them, 

 than may suffice to indicate the boundaries of 

 the three groups under which we have ar- 



ranged them. It is probable that in almost 

 every act of secretion a double purpose is 

 served, the blood being freed from some in- 

 gredient whose accumulation would be super- 

 fluous, if not injurious ; and the fluid sepa- 

 rated having some secondary purpose to 

 answer. Thus, whilst biliary matter becomes 

 a positive poison if it be retained in the blood, 

 it serves an important purpose, when poured 

 into the duodenum, in completing the diges- 

 tive process, and in preparing the nutrient 

 contents of the intestinal canal for absorption. 

 So, again, the cutaneous exhalation not only 

 removes the superfluous water of the blood, 

 but is one of the chief means of regulating the 

 temperature of the body; whilst the sebaceous 

 matter, poured forth by the glanclulae of the 

 skin, serves to lubricate its surface, at the 

 same time that it relieves the blood of matter 

 which, not being nutritive, is extraneous. 

 Even the urine, which seems to be eliminated 

 merely for the removal of noxious matters 

 from the blood, is sometimes made to serve 

 an additional purpose, its acridity, or its pe- 

 culiarly offensive odour (increased under the 

 influence of terror), frequently rendering it an 

 effectual means of defence. On the other 

 hand, the substances which are separated 

 from the blood for the purpose of discharging 

 some important office in the economy, usually, 

 if not always, contain some substances whose 

 retention in the blood would be injurious, 

 and which are therefore advantageously got 

 rid of through this channel. Thus the sa- 

 livary, the gastric, and the pancreatic fluids all 

 contain an animal principle nearly allied to 

 albumen ; but this principle seems to be in a 

 state of change, or of incipient decomposition ; 

 and it would seem not improbable, that whilst 

 this very condition renders the albuminous 

 matter useful in promoting the solution of the 

 aliment, it renders it unfit to be retained 

 within the circulating current. 



It is impossible, therefore, to divide the 

 secreted products strictly, as some have at- 

 tempted to do, into the excrementitious and 

 the recrementitious ; that is, into those which 

 are purely excretory in their character, and 

 those which are subservient to further uses in 

 the economy ; most, if not all of them, par- 

 taking more or less of both characters. Still 

 we may group the secreting processes for 

 practical purposes, according to the predo- 

 minance of one or other of the objects enu- 

 merated above; those being arranged under 

 the first division, in which the depuration of 

 the blood is manifestly the chief end, any 

 other being rendered subservient to this, as is 

 the case pre-eminently with regard to the 

 urine ; those being classed under the second, 

 in which the ulterior purpose of the separated 

 fluid would seem to be the principal occasion 

 of its production ; and this second group 

 being subdivided, according as this ulterior 

 purpose is connected with the operations of 

 the economy itself, as is that of the tears, the 

 saliva, the gastric fluids, &c., or is destined to 

 act upon some other, as is the case with the 

 milk, the odorous secretions, &c. 



F F 4 



