970 Proceedings of the Royal Society 
of automata — of both in so far as they are not interchange- 
able. This increase of animal automata (given that supply of tran- 
sitory ultimate products known as the standard of comfort) is 
attained by reproduction, and increase of a given class of population 
is therefore determined by the amount of the transitory ultimate 
products supplied — and hence by the “ capital invested ” in that 
industry. Increase of permanent products, on the other hand, does 
not tend to increase the population. The reproductive ratio of any 
class of producers per unit time is thus a fixed and definite one, 
and approximately ascertainable. {Cf. Appendix to Chap. I. § 28.) 
The multiplication or decrease of any class of the community is, 
in short, strictly comparable to the hypertrophy or atrophy of the 
cells of an organ in proportion to its functional activity and nutri- 
tive supply. {Cf. article “Reproduction’’ — Encydopcedia Britan- 
Tiica.) 
Appendix to Chapter II. — Practical Biological Economics. 
§ 37. Practical Biological Economics . — As in the case of physical 
economics, so here we have two alternative practical ideals : 
1. To maximise the maintenance and evolution of the com- 
munity. 
2. Or to minimise the same. 
All action is referable to either of these categories, and tends neces- 
sarily in one of those directions. As practical economists, we are 
shut up to the selection of the first, and we have only to consider 
how this ideal can best be realised. This involves a criticism of 
life from a biological standpoint ; a subject analy sable into endless 
detail, e.g., the criticism of production alone embracing processes so 
apparently remote as food-analysis and art-criticism. The details of 
such a discussion cannot be given here, but the lines to be followed 
may be indicated. The modifications of the organism must be 
determined and analysed into their various factors, viz., (1) the 
effects of organism on organism in heredity (education and compe- 
tition) j (2) the influence of function on the organism towards 
degeneration on the one hand, and towards evolution on the other ; 
(3) the modification of the organism by its material environment, 
such as food, dwelling, air, light, &c. Not only must these factors 
