fashioned animal breeders, the advantage of the new methods over the old must be apparent. Instances of this kind give us good reason for believing that before many years have passed useful forms of animals and plants will be produced on demand, not in the somewhat haphazard way of the present practise of breeders, but with the certainty and precision with which a modern inventor constructs a new piece of machinery.
This change in the aspect of evolutionary matters can not be better illustrated than by three quotations that preface one of the most important publications on evolution in the last decade, "Species and Varieties, their Origin by Mutations." The quotations, which are arranged in historical sequence and come from the three great masters in this field, are as follows:
The origin of species is a natural phenomenon.—Lamarck.
The origin of species is an object of inquiry.—Darwin.
The origin of species is an object of experimental investigation.—De Vries.
The last statement, that the origin of species is open to experimental study, is the keynote to modern evolutionary work. But it is not simply the keynote to this particular part of biology; it marks a change in front of the whole army of biological workers whereby the science of the organism is being transformed from one of observation pure and simple to one which includes experiment. We sometimes hear astronomy, chemistry, physics, etc., described as the exact sciences, and our friends in these domains of knowledge occasionally take a hidden pleasure, I suspect, in intimating that what lies outside their realm, including biology, must belong to the inexact category. That biology has not been exact in the sense that physics and chemistry have been, we freely admit, but physics was not always exact, and before the days of Lavoisier, chemistry had few quantitative results of which it could boast. Biology, from the nature of the materials it has had to master, has of necessity been slow in growing to that stage where it was imperative to use those refined methods that have long been employed by physics and chemistry. But these methods are rapidly being assimilated by the more progressive members of the biological fraternity, who are discovering that there is nothing inherently inexact about the subject-matter of biology or its treatment. This subject-matter is open to the same searching method as is that of the so-called exact sciences. But though we are not yet admitted to full fellowship with these sciences, we are at least the center of the observational group and, if we wished to retaliate on our good friends of the exact sciences, we might declare them non-observational with as much reason as they call us inexact. But you will accuse me of falling into a word controversy. And such it would be. The truth is that biology is rapidly becoming experimental, and in doing so it necessarily assumes all those methods and procedures that have long been
