CUTANEOUS AND MUCOUS FOLLICLES. 663 



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 accu- 

 mulate on the surface of the skin ; and its character can only, therefore, be 

 stated approximately. It has usually an acid reaction, which seems due to 

 the presence of acetic acid ; and to this, or to lactic acid, we are probably to 

 attribute the sour smell which it has, especially in some disordered states of 

 the system. The proportion of solid matter, according to Anselmino, varies 

 between 5 and 12'5 parts in 1000. The greatest part of it consists of animal 

 matter, which is apparently a proteine-compound in a state of incipient decom- 

 position. The remainder consists of saline compounds ; 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 Sudo- 

 riferous glands ; the greater part, under ordinary circumstances, being the 

 product of simple Evaporation, by which, of course, nothing but pure watery 

 vapour is dissipated. 



870. The entire amount of fluid which is insensibly lost from the Cutaneous 

 and Pulmonary surfaces, is estimated by Seguin at 18 grains per minute ; of 

 which 11 grains pass off by the skin, and 7 by the lungs. The maximum 

 loss by Exhalation, cutaneous and pulmonary, during twenty-four hours, (ex- 

 cept under very peculiar circumstances,) is 5 Ibs. ; the minimum 1 Ib. It 

 varies greatly, according to the condition of the atmosphere, and that of the 

 body itself. The manner and degree in which it is influenced by atmospheric 

 conditions, will be better discussed under the head of. Animal Heat ( 897); 

 since this influence has a most important effect in the regulation of the tem- 

 perature of the body. As already pointed out, the Urinary excretion is in 

 great degree vicarious with it, in regard to the amount of fluid discharged. 

 the urine being more watery in proportion as the Cutaneous Exhalation is 

 diminished in amount, and vice versa ( 840). But we are also to look at 

 these two excretions as vicarious, in regard to the deportation (or getting rid) 

 of the products of the waste of the system. The share which the Skin has 

 in this office has probably been generally under-rated. There is reason to 

 believe that at least 100 grains of azotized matter are excreted from it daily; 

 and any cause which checks this excretion, must throw additional labour on 

 the kidneys, and will be likely to produce disorders of their function. 



871. The Exhalant action of the Skin is influenced by general conditions of 

 the vascular and nervous systems; which are as yet ill understood. It is quite 

 certain, however, that through the influence of the latter the secretion may 

 be excited or suspended ; this is seen on the one hand in the state of syncope, 

 and the effects of depressing emotions, especially fear, and its more aggravated 

 condition, terror ; and on the other in the dry condition of the skin during 

 states of high nervous excitement. It is very probable that, in many forms of 

 fever, the suppression of the perspiration is a cause, rather than an effect, of 

 disordered vascular action ; for there are several morbid conditions of large 

 parts of the surface, in which the suppression of the transpiration appears to 

 be one of the chief sources of danger, having a tendency to produce congestion 

 and inflammation of internal organs. From the recent experiments of Dr. 

 Fourcault,* it appears that complete suppression of the Perspiration in animals. 



* Comptes Rendus de 1'Academie, May, 1844; and Lancet, June 8, 1S44. 



