IIO VITALITY. 



Each spherical particle is free to move in fluid, and the 

 intervals between the particles are occupied by fluid. This 

 fluid contains, in solution, 



1. Matter about to become living; 



2. Substances which exert a chemical action, but do 

 not necessarily form a constituent part of the living mass, 

 together with particles which are rejected, and not capable 

 of being animated ; and 



3. Substances resulting from the changes ensuing in 

 particles which have arrived at the end of their period of 

 existence, and the compounds formed by the action of 

 oxygen upon these. 



There can be no doubt that the smallest particle of 

 living matter is complex. It is impossible to conceive 

 the existence of a living particle of any simple substance 

 like iron, oxygen, nitrogen, &c. ; for living involves changes 

 in which several different elements take part. It seems 

 to me, therefore, that the term living atom cannot with 

 propriety be employed, seeing that living matter is of 

 complex composition, while the idea of an atom seems to 

 nvolve simplicity of constitution, if not indivisibility. The 

 whole question of the arrangement and form of the atoms 

 in living matter can at present only be discussed theoreti- 

 cally ; and I would now merely remark with reference to 

 this subject, that although all living particles are of complex 

 composition, many different elements may exist in very 

 different proportions in living matter; and that there is 

 reason to believe that the smallest particles of every kind of 

 living matter are spherical. It is not possible to see, with 

 the highest powers now made, particles which would in all 



