448 Proceedings of the Royal Physical Society. 



would comprise influences such as pressure, heat, and light. 

 The clear division into physico-chemical, biological, and 

 psychological has also been suggested, the first being in- 

 animate factors, the second animate, and the third including 

 those influences which influence the minds (if we may so 

 speak) of animals rather than their bodies. The last-mentioned 

 influences are doubtless very important, especially for a 

 Lamarckian, but they hardly come within our present limits. 

 In Comte's plan of a biological course, the environment was 

 resolved into two portions, to which a third was afterwards 

 added : (1) astronomical, chemical, and physical factors ; (2) 

 soil, atmosphere, and water ; and (3) the animate surround- 

 ings, both quantitative and qualitative. The following 

 scheme exposes a more detailed combination of previous 

 suggestions. 



