EUGENICS RECORD OFFICE. 



155 



STATISTICS OF ANCESTRAL INFLUENCE. 



Work on mechanical devices for demonstrating the mathematical 

 formulae of heredity was continued by Dr. Laughlin. A machine was 

 perfected for aiding the formulation of the mathematical aspects of the 

 segregation and recombination of chromosomes in passing from genera- 

 tion to generation. Twenty-eight formulae which present general 

 mathematical pictures of hereditary processes were developed; these 

 were described in a paper entitled ''Calculating ancestral influence in 

 man," read before the National Academy of Sciences at New Haven, 

 Connecticut, November 10, 1919. Work on a series of calculations for 

 formulating the mathematical aspects of the ''Pure-sire system of 

 breeding" and the "Measure of consanguinity" were begun and are 

 progressing satisfactorily. 



ARCHIVES. 



The care of the archives has remained in the hands of Miss Louise 

 Nelson. The following is a simamary of material added to the archives, 

 September 1, 1919, to September 1, 1920: 



I. Index cards: 



1. Main index 68.167 



2. Persons index 3,910 



II. Manuscript material: 



1. Field reports 5,951 



2. Miscellaneous 



III. Special schedules: 



1. Record of family traits 



2. Family distribution of per- 



sonal traits 



3. Twin 



4. Weight 



5. Eye, hair, and skin color . . . 



6. Other, including polydactyl- 



ism, left-handedness, tu- 

 berculosis, deafness, etc . . 



751 



351 



3 



128 



32 



17 



59 



IV. Miscellaneous material: 



1. Individual analysis cards. . 



2. Genealogical data cards . . . 



3. Biographical data cards . . . 



4. Newspaper clippings: 



a. Biographical 27,048 



h. Genealogical 7,600 



V. Books: 



1. Biography 



2. Collective biography 



3. Genealogy 



4. Town history 



5. Miscellaneous pamphlets . . 



246 

 157 

 150 



130 



32 



10 



9 



76 



Up to the present time there is a total of 752,231 cards in the Sex- 

 tuple Index and 4,500 in the Persons Index. And since each card 

 affords space for 40 entries, and, as some contain this number and 

 many others as many as from 4 to 10, it is probable that there are more 

 than 2,000,000 entries on file. Of the Record of Family Traits sched- 

 ules there are over 3,500. 



From the books received, 10,058 pages have been indexed, but be- 

 cause of lack of filers it has not been possible to add this material 

 to the main card-index. In addition to this, 4,272 sheets containing 

 461,376 entries made from manuscript material have also been accu- 

 mulated. 



During the summer we were able to make use of the assistance of a 

 number of college students, some of whom were doing other work at 

 Cold Spring Harbor, in the preparation of material for the archives and 

 in the analysis of the records. Mr. William Kraus assisted in the analy- 



