This exhibit consists of a series of blank record forms designed to +illustrate the method of keeping pedigree records+ which has been in use at the Maine Agricultural Experiment Station for a period of five years, in connection with its work in the experimental study of inheritance in poultry and in various plants. The advantages which have been found by experience to inhere in this system of pedigree record keeping are (_a_) simplicity; (_b_) ease of operation; (_c_) small chance for error in the keeping of large masses of pedigree records; (_d_) uniformity of the system, such that records of all kinds, in any way pertaining to the work, may be brought together with great ease for consultation or study. In addition to the record blanks there are exhibited also various marking devices and other apparatus connected with the proper working of the plan. It should be noted that while the blanks here exhibited are devised particularly for work with poultry and plants, the same system, with slight modifications, may be successfully applied to the keeping of human pedigree records; indeed it is a pleasure to state that the system here exhibited is an outgrowth and development of a scheme for the keeping of pedigree data in general and particularly human pedigree records suggested many years ago by the late Sir Francis Galton. * * * * * [Sidenote: H] Exhibited by C. V. Drysdale, Esq., D. Sc. The +Malthusian theory of population+ leads to the conclusion that the population of the majority of countries is held in check by lack of food. Therefore, there should be a correspondence between the birth and death rates, high birth rates producing high death rates and high infantile mortality, and the death rate should rise or fall with a rise or fall of the birth rate. In the accompanying diagrams, white strips imply birth rates, shaded strips death rates, and black strips infantile mortality, or deaths of children under one year. [Sidenote: H 1] Shows the relation between +birth and death rates and infantile mortality+ in various countries in 1901-1905. [Illustration: VARIOUS COUNTRIES 1901-05 Figure H 1.] [Sidenote: H 2] Relation between _birth rate and +corrected+ death rates_ in various countries. (This shows that France is healthier than appears in H 1.) [Sidenote: H 3] Shows relation between +birth and death rates+ from various causes in five districts of +London+. [Sidenote: H 4] Relation between the +birth rate and death rate+ for various arrondissements of +Paris+ in 1906. (Note that the increase in the Elysée quarter is as high as the average in the quarters of high birth rate.) [Sidenote: H 5-6] Variation of the +total population and birth and death rates+ in the +United Kingdom+ and the +German Empire+. (Note that the fall in the death rate corresponds fairly closely to that in the birth rate.) [Sidenote: H 7] Id. for +France+. (Note that the population is still increasing although slowly.)