340 DR ALISON'S OBSERVATIONS ON 



going on in the textures while life continues, is due to the partial loss of vital 

 power of these textures themselves, and is the cause, rather than the conse- 

 quence, of the agency of oxygen upon them. 



When we consider, farther, how exactly this is in conformity with the gene- 

 ral fact, that all other kinds of vital action are essentially temporally, — that all 

 nervous actions, and all muscular contractions, necessarily alternate with periods 

 of repose, — I think we can have no difficulty in acquiescing in the general law of 

 all Vital Affinities, at least so far as animals are concerned, which explains at 

 once the necessity of constant nutrition of all animal bodies (even when their 

 weight is stationary or declining), the principle of interstitial absorption, the use 

 of respiration, the maintenance of animal heat, and the necessity and nature of 

 the excretions ; viz., that as the perpetuation of each species is provided for only 

 by the successive life and death of numberless individuals, so the life of each in- 

 dividual is sustained only by the successive life and death of all the portions of 

 matter of ivhich its body is composed; and that each portion, as it dies, falls 

 under the power of the oxygen absorbed from the atmosphere, as it would do 

 in the dead body, and enters into new combinations which are injurious to the 

 living system, but pass off by the excretions ; gradually reverting to those inor- 

 ganic compounds, from which the power of vegetable life only can again raise 

 them to the condition of organized and living matter. 



The general conclusions regarding Vital Affinity, which seem to me to be 

 warranted by this review of the subject, and to l)e sufficiently established to be 

 stated as principles in Physiology, are the following : — 



1. That it is by a power peculiar to the state of life, and equally vital as the 

 irritability of muscles, but varying in the diflFerent parts of each organized struc- 

 ture, that the solids, and especiall}' the cells of organized matter, attract, se- 

 lect, consolidate, and aiTange in their substance, and within their cavities, cer- 

 tain substances, usually compound, which are brought into contact with them, and 

 reject or exclude others. 



2. That in the cells of organized matter, during the living state, and ap- 

 parently by an influence of these cells analogous to that chemical influence to 

 which the term Catalysis has been applied, analogous also to fermentation, certain 

 definite transformations of chemical elements take place, which are equally pe- 

 culiar to the state of life ; Avhich transformations, at least in animals, appear to be 

 effected more in the cells or corpuscles which float in the fluids, than in those 

 which compose the solid part of the structure. 



3. That although we ha-ve proof that the origin of all the organized beings now 

 seen on the earth's surface has been of recent date, in comparison with the earth 

 itself, we see these powers, thus exercised, continually transmitted to successive 

 sets of cells in each individual, and to successive generations of individuals, with- 



