the juridical and political superstructure, so many of the new biological and geological theories recognize alongside of the slow accumulation of slight and even infinitesimal alterations, also sudden profound transformations—catastrophies —that arise from the slower evolution.
A notable example of this is furnished by the observations of de Bries reported at the last Congress of Natural Sciences held at Hamburg. He has discovered that the species of plants and animals remain unchanged through a long period; some of them finally disappear, when they have become too old to longer adapt themselves to the conditions of existence, that have in the meantime been changing. Other species are more fortunate; they suddenly "explode," as he has himself expressed it, in order to give life to countless new forms, some of which continue and multiply, while the others, not being adapted to the conditions of existence, disappear.
I have no intention of drawing a conclusion in favor of revolution from these new observations. That would be to fall into the same error as those who argue to the rejection of revolution from the theory of evolution. But these observations at least show that the scientists are themselves not wholly agreed as to the part played in organic and geologic development by catastrophies, and for this reason it would be an error to attempt to draw from either of these hypotheses any fixed conclusions
