sufficiently complete record of his own ancestry would necessarily be able by inspection to deduce from it any important contribution to science. But if enough complete family records are made available, the professional geneticist can be called into cooperation, can supplement the human record with his knowledge of the results achieved by carefully controlled animal and plant breeding, and between them, the genealogist and the geneticist can in most cases arrive at the truth. That such truth is of the highest importance to any family, and equally to society as a whole, must be evident.
Let the genealogist, then, bring together data on every trait he can think of. As a guide and stimulus, he should read the opening chapters of Herbert's Spencer's Autobiography, or of Karl Pearson's, Life, Letters and Labors of Sir Francis Galton, or C. B. Davenport's study55 of C. O. Whitman, one of the foremost American biologists. He will also find help in Bulletin No. 13 of the Eugenics Record Office, Cold Spring Harbor, Long Island, New York. It is entitled, How to Make a Eugenical Family Study, and gives a list of questions which should be answered, and points which should be noted. With some such list as this, or even with his own common-sense, the genealogist may seek to ascertain as much as possible about the significant facts in the life of his ancestors, bearing in mind that the geneticist will ask two questions about every trait mentioned:
- Is this characteristic inherited?
- If so, how?
Nor must it be forgotten that the geneticist is often as much interested in knowing that a given character is not inherited under certain conditions, as that it is.
It is highly desirable that genealogists should acquire the habit of stating the traits of their subjects in quantitative