337 



relations alone — the molecular collocation — wliich is never 

 the same from one moment of time to another, but its adap- 

 tability to the environment which constitutes life. As Mr. 

 Spencer remarks, " an individual homogeneous throughout, 

 and having its substance everywhere continuously subject to 

 like actions, could undergo none of those changes Avhich life 

 consists of."^ Colloids which are the nearest approach in in- 

 organic matter to that which is living, tend under uniform 

 conditions to pass from unstable to stable or crystalloid 

 equilibrium, and such a condition of perfect equilibrium is 

 a condition of lifelessness or death. Life does not consist in 

 either the internal or external relations of a body separately, 

 but in their continuous mutual adjustment ; molecular 

 constitution is only one of the elements of life. 



Dr. Bastian, nevertheless, considers that '' monads and 

 bacteria are produced as constantly in solutions of colloidal 

 matter as crystals are produced in solutions of crystallisable 

 matter," and that the difference between the products "may 

 be due simply to the original difference in nature between 

 such kinds of matter."^ Primd facie the analogy seems a 

 strong one; in either case a substance at first diffused in 

 solution, and therefore amorphous, finally segregates witli 

 the assumption of definite form. Furtlicr consideration, how- 

 ever, shows that this view is not free from difficulty, and 

 leaves room for doubt whether it really describes the true 

 state of the case. It seems clear that the form of an aggre- 

 gate so produced must have some relation, Avhether a crystal 

 or a living thing, to the form of its component units, and 

 must be more or less implicitly determined by it. What 

 explanation otherwise can be given of the constancy with 

 which shapes identical, or generally siniilar, recur ? The 

 form of the aggregate would be purely arbitrary if the units 

 had no influence in determining it. In the case of crystal- 

 loids there are many reasons for believing that the moderate 

 number of atoms composing their molecules may, in obedience 

 to their mutual but diverse polarities, arrange themselves in 

 a definite form having a definite resultant polarity. Such a 

 molecular system may be subject to disturbance, and finally 

 rearrangement by the incidence of external forces, such as 

 light or heat, so that a substance chemically the same may 

 possess several allotropic crystalline conditions. But the 

 molecules of colloids are highly complex, consisting of a vastly 

 greater number of atoms, any arrangement of which must 

 tend to be spherical, and therefore Avith no marked resultant 



^ 'Principles of Biology,' vol. i, p. 286. 

 ° 'Nature,' vol. ii, p. 172. 



