of small «fluctuating » variations is the primary and fundamental, if not the sole method of organic evolution. Such an idea is, of course, absurd. The purpose of biometrical study so far as it is applied to the evolution problem is precisely to find out what has been the method of evolution. Whatever the result of such inquiry may turn out to be has no relation to either the validity or usefulness of biometric methods per se. The statistical methods or calculus developed by Pearson are particularly adapted to the study of variation of the continuous fluctuating type, but one who uses this calculus is in no way compelled because of this fact to take any particular position in regard to the question of the biological importance or significance of this kind of variation in evolution. This is a matter to be settled by direct experiment and observation. If, as many biologists are coming to believe, this type of variation has, in a strict sense, very little if any significance in evolution biometric methods will help to demonstrate the fact. Further, as has been implied above, the statistical study of variation is only one side of biometry.
Based on a misconception similar to that just discussed in the point of view which criticises biometry as being necessarily tied fast to a particular view regarding the hereditary process. The «law of ancestral inheritance » first enunciated by Galton and later extensively developed by Pearson is simply a statistical statement. It concerns itself with the end results of the action in a general population of a whole complex of biological processes, of which inheritance is only one. It is the writer's opinion that this «law » probably has very little direct relation to the really significant basic facts of heredity, and that whatever apparent significance it may have is largely accidental and fortuitous. But whether this opinion is correct or not certainly has no bearing on the question of the validity of bringing « appropriate » and « correct» mathematical methods to the aid of the investigator wherever they can be of help in solving problems. It is a confusion of thought to criticise a scientific method of investigation because of the theoretical views held by some of those who employ it. There is yet to be discovered a scientific method which can be depended upon to give correct results invariably, regardless of how it is handled or applied. Biometry is no worse off
