Page:JehuTJ 1902redux(1).pdf/7

6

If variation is frequently discontinuous and large in amount, as the evidence seems to show, it is possible, as was long ago suggested by Geoffry St. Hilaire, that there may have been leaps and bounds in Evolution. Mr. Bateson suggests that in these discontinuous variations we may often find the variations out of which new species arise. In that case natural selection is not such an important factor in the origin of species as the Darwinians have supposed. Other naturalists, notably De Vries, have within recent years recognised the existence of discontinuous variations. Bateson confined himself for most part to the study of variations in the number, symmetry, and arrangement of parts; to these variations he applies the term merislee
mircolic. The discontinuity between variations is seen in the repetition of parts; and in the phenomenon of symmetry. Sudden and complete changes in colour are also often seen and numerous examples among plants are given by De Vries. Mr. Bateson also points out that there is a greater definiteness of variation than has been generally recognised by Darwinians. This raises one of the most important problems which has to be solved concerning the nature of variations, namely, the question of whether variations are always haphazard or whether they occur in definite directions. During the last few years many biologists have come to the conclusion that variations are determinate. The study of fossils has led the American paleontologist to adopt this view. And it