OF SECRETION IN GENERAL. 



467 



relief. Still more obviously vicarious, however, are the Kidneys and the 

 Skin ; for here we find that not only do the kidneys allow the transudation 

 of whatever superfluous water may remain in the circulating current, after 

 a sufficient amount has been exhaled from the skin to keep down the tem- 

 perature of the body to its normal standard, but the skin actually assists in 

 the elimination of one of those products of the metamorphosis of the azo- 

 tized tissues, the removal of which has been until recently considered as the 

 special function of the kidney. Consequently, whenever the due action of 

 the skin as an excreting organ is interfered with, it is the kidney especially 

 that will be called on to take its place; whilst, on the other hand, if it be 

 thought desirable to relieve the kidney, this may be most effectually done 

 by stimulating the skin to increased excretory activity. This vicariousness 

 of function among the Excretory organs presents itself far more remarkably, 

 however, in certain states of disease; in which a complete "metastasis of 

 secretion" may exhibit itself. The capability of one organ thus to take 

 upon itself the special action of another, appears to be related to the "com- 

 munity of function" existing in the secretory surface among those lower 

 animals, which manifest none of the "specialization" or setting apart for 

 particular offices, that we see in the higher ; for it seems to be a general law 

 in Physiology, that, even where the different functions are most highly spe- 

 cialized, the general structure retains, more or less, that primitive com- 

 munity of action which characterized it in the lowest grade of development. 1 

 384" It is in regard to the Urinary excretion, that the evidence on this 

 point is most complete ; for it seems to be established by a great mass of 

 observations, that urine, or a fluid presenting its essential characters, may 

 pass off by the mucous membrane of the intestinal canal, by the salivary, 

 lachrymal, and mammary glands, by the testes, by the ears, nose, and navel, 

 by parts of the ordinary cutaneous surface, and even by serous membranes, 

 such as the arachnoid tunic lining the ventricles of the brain, the pleura, and 

 the peritoneum. A considerable number of such cases was collected by 

 Haller; 2 many more were brought together by Nysten ; 3 and more recently 

 Burdach 4 has furnished a full summary of the most important phenomena 

 of the kind ; and Dr. Laycock 5 has compiled a valuable collection of cases 

 of urinary metastasis occurring as complications of hysteria. The following 

 table of cases referred to by the last of these authors, will give some idea of 

 the relative frequency of the different forms of this curious affection : 



It is to be borne in mind, however, that cases of hysterical ischuria are 

 frequently complicated with that strange moral perversion, which leads to 

 the most persevering and ingenious attempts at deceit ; and there can be 

 little doubt that a good many of the instances on record, especially of urinous 

 vomiting, are by no means veritable examples of metastasis. The proofs of 

 the fact we are seeking to establish are, therefore, much more satisfactory 

 when drawn from experiments upon animals, or from pathological observa- 

 tions, about which, from their very nature, there can be no mistake. Thus 



1 See Princ. of Comp. Phys., \\ 110, 428. 



2 Elementa Physiologise, torn, ii, p. 370. 



3 Kecherehes de Physiologic et de Chimie pathologiques, p. 265. 



4 Traite de Physiologie (Jourdan's translation), vol. viii, p. 248 et seq. 



6 Edinb. Med. and Surg. Journ., 1838; and Nervous Diseases of Women, p. 233. 



