THE ANCESTRY OF THE LONGLIVED.
By Raymond Pearl '99 and Ruth DeWitt Pearl. The Johns Hopkins Press. We used to compute all kinds of correlation coefficients which we thought meas ured correctly to at least three decimal places the correlation between the ages of death of a large group of people and the ages of death of any specified immediate ancestor until we began to appreciate the multiplicity of factors involved. The results published in this little book of 168 pages are anything but startling or sensational but they are sound and reliable.
Two groups of people or series are studied and compared one, the larger and including 1579 living people, males and females (called the Long series), who are over ninety years of age and secured by extensive questionnaires; and the other, a smaller group covering some 143 case histories taken at random, except that they are the only ones which had complete records of longevity of parents and grandparents, from the Family History Records (therefore called the FHR series) of the authors' department.
Some of the most interesting numerical results were obtained by comparing the values of the novel unit TIAL (Total Immediate Ancestral Longevity) the sum of the ages at death of the two parents and four grandparents. TIAL for the Long series ranged from 254 to 599 years a range which extended beyond that of the FHR series at both ends. The median of the former exceeded that of the latter by about 16 per cent. On the average each additional 3.7 years in TIAL was found to promise an additional year for the offspring called here the propositus. Little evidence was produced bearing one way or the other upon the inheritance of longevity in accordance with any Mendelian theory. Comparisons are made also with results of many other and earlier investigations by others.
Other features are considered (other than longevity) such as geographical origin, use of alcohol, etc. Incidentally, the results showed no serious effects of moderate use of alcoholic beverages.
It was found necessary to include accidental deaths because of the lack of a satisfactory line of demarkation but the authors make a good case for their belief that this apparent defect is in favor of their results being safe minimums. Few of a multitude of correlations prove significant.
The little book is so concentrated from a much larger volume of results distributed throughout a series of journal articles that it is impossible for a reviewer to do the book justice. For a satisfactory appreciation the reader must go to the book itself but as the authors suggest the reader should be really interested in the problems of longevity, otherwise he will not find the book easy reading.
