184 SPENCER'S PHYSIOLOGICAL UNITS. 



ceive with regret, does not mention Fletcher. Per- 

 haps, as he is not a professed physiologist, he may not 

 have heard of him, but what are we to say to the fact 

 that he does not mention Beale, whose lectures had 

 appeared four years before ? It would have been 

 better if he had studied both these authors, for his 

 theory is at present most imperfect, and will bear no 

 comparison with the complete protoplasmic theory of 

 Fletcher and Beale. Indeed, it has the appearance of 

 an afterthought, when, on reflection, he perceives that 

 colloidality, instability, osmosis, arid other chemical 

 and physical properties to which he attributes a large 

 portion of the functions of living beings, hastily named 

 by him vital, are wholly unable to throw any light on 

 the really and distinctively vital actions. The imper- 

 fection of the theory is shown on attempting to adapt 

 it to the phenomena of life on frequent occasions. For 

 instance, in attempting to explain evolution, he says 

 (vol. ii. p. 11) : " Such being the primitive physio- 

 logical units, organic evolution must begin with the 

 formation of a minute aggregate of them an aggre- 

 gate showing vitality only by a higher degree of that 

 readiness to change its form of aggregation which col- 

 loidal matter in general displays, and by its ability to 

 unite the nitrogenous molecules it meets with into 

 complex molecules like those of which it is composed." 

 Now, granting that we have got our complex units, 

 see here how the grand characteristic of living matter 

 is slipped in as a thing of little consequence, and quite 

 on a par with the colloidal instability supposed to be- 

 long to living matter, but does not. This faculty of 

 combining heterogeneous compounds into matter like 



