For like reasons the process must repeat itself in each of the componentmasses of units that are differentiated by the modifying forces. Each ofthese minor groups, like the major group, must gradually, in obedience tothe unlike influences acting on it, lose its balance of parts, and pass froma uniform into a multiform state. And so on continuously. Whence, indeed,it follows that not only must the homogeneous lapse into non-homogeneous,but the more homogeneous must tend ever to become less homogeneous. If anygiven whole, instead of being absolutely uniform throughout, consist of partsdistinguishable from one another -- if each of these parts, while somewhatunlike other parts, is uniform within itself; then, each of them being inunstable equilibrium, it follows that while the changes set up within itmust render it multiform, they must at the same time render the whole moremultiform than before. The general principle, now to be followed out in itsapplications, is thus somewhat more comprehensive than the title of the chapterimplies.
No demurrer to the conclusions drawn, can be based on the truth that perfecthomogeneity nowhere exists; since, whether that state with which we commencebe or be not one of perfect homogeneity, the process must equally be towardsa relative heterogeneity. §150. The stars are distributed with a threefold irregularity. Thereis first the marked contrast between the Milky Way and other parts of theheavens, in respect of the quantities of stars within given visual areas.
There are secondary contrasts of like kind in the Milky Way itself, whichhas its thick and thin places; as well as throughout the celestial spacesin general, which are more closely strewn in some regions than in others.
And there is a third order of contrasts produced by the aggregation of starsinto small clusters. Besides this heterogeneity in the distribution of stars,considered without distinctions of kind, a further heterogeneity is disclosedwhen they are classified by their differences of colour, which answer todifferences of physical constitution. While yellow stars are found in allparts of the heavens, red and blue stars are not so: there are wide regionsin which both red and blue stars are rare; there are regions in which theblue occur in considerable numbers, and there are other regions in whichthe red are comparatively abundant. Yet one more irregularity of like significanceis presented by the nebulae. These are not dispersed with anything like uniformity,but are far more numerous around the poles of the galactic circle than inthe neighbourhood of its plane.
No one will expect that anything like a definite interpretation of thisstructure can be given on the hypothesis of Evolution, or any other hypothesis.
