OF FREE NUCLEI AND THEIR ACTIONS. 137 



for the maintenance of its vital activity ; whilst others modify and pervert that 

 activity without destroying it, so as to give rise to morbid actions; the effects 

 of others, again, being so completely antagonistic to all vital activity, that it is 

 at once checked by them. And we shall hereafter see reason to believe, that 

 just as the unorganized pabulum provided for the nutrition of the structure, is 

 converted by the act of Organization into the living cell, so the Physical and 

 Chemical forces whose influence promotes that organization are really metamor- 

 phosed (so to speak) into Vital power by the instrumentality of the cell-germ, 

 so that all the forms of " cell-force" are thus immediately derived from them. 

 It is, however, inherent in the very nature of the living organism that this 

 instrumentality should only persist for a limited time. The changes involved 

 in the process of organization have the effect of rendering the organic structure 

 less and less instrumental in determining this metamorphosis of force; and thus 

 a time arrives, when the capacity of development is exhausted, and when the 

 physical and chemical forces, no longer turned to the account of vital activity, 

 begin to exert a disintegrating power. Hence in the Life of each cell, there is 

 a period in which its peculiar attributes are undergoing augmentation, an epoch 

 of perfection, a period of decline, and an epoch of entire cessation ; and the latter 

 is forthwith succeeded (save in the exceptional cases already referred to, 114), 

 by the decay of the structure. And in proportion to the degree of vital energy 

 which the cell possesses (that is, to its power of turning Chemical and Physical 

 agencies to its own account, instead of being itself perverted by them), will it 

 be able to resist the operation of influences which tend to its disintegration. All 

 this is true, as will be shown hereafter (SECT. 3), of the organism at large, as 

 well as of the single cell ; in fact, the entire organism, commencing in a single 

 cell, and developed through the multiplication of cells, may be considered, even 

 at its fullest development, as exhibiting, distributed (as it were) through its 

 various component parts, all those attributes which have now been described as 

 characteristic of cells in general; and the phenomena, not merely of normal life, 

 but of disease, and of the influence of morbific and remedial agents, will be found 

 to be so many illustrations of the doctrines now enunciated. It is indeed sur- 

 prising, that with this mass of familiar facts continually presenting themselves 

 to the observation of Physiologists, any such doctrine should have held its ground, 

 as that the living organism withdraws its components from the domain of Phy- 

 sical and Chemical forces; and only restores them to the authority of these, 

 when it has itself lost the supremacy of the "Vital Principle" or "Organic 

 Agent" which was supposed to hold possession of the living organized body. 



117. Of Free Nuclei and their Actions. Although the " Cell" has been 

 spoken of as the type of organic structure, and the " Cell-force" as the most 

 general form of vital agency, yet it must not be left out of view that there is 

 strong evidence of the presence of similar attributes in bodies resembling cell- 

 nuclei, which, although they may never go on to be developed into cells, appear 

 to be the instruments of vital operations of a very determinate kind. This is espe- 

 cially the case, as first pointed out by Mr. Simon, 1 in the case of the so-called 

 " Vascular Glands," whose elaborating influence is exercised upon materials which 

 are withdrawn from the current of the circulation only to be restored to it again ; 

 there being here obviously not the same necessity fora limitary membrane, as where 

 the material drawn by the nucleus of the secreting cell around itself, is destined 

 to be completely separated and to be cast forth through another channel. There 

 are various cases, however, even among the ordinary secreting structures, in 

 which the cell-membrane seems to be wanting, free nuclei being found both in 

 the organ and in the secreted fluid ; this is especially the case, for example, in 

 the gastric glands. And generally it may be remarked, as Mr. Simon has pointed 



1 "Physiological Essay on the Thymus Gland," p. 84. 



