The Study of Human Heredity. 3 



N. J., and Drs. A. C. Rogers of Faribault, Minn., Wm. Healy of 

 Chicago, 111., Wm. T. Shanahan of Sonyea, N. Y., and David F. 

 Weeks of Skillman, N. J. 



The system is a rectangular one, the symbols for the individuals 

 (individual symbols) of a fraternity (full brothers and sisters) being 

 on the same horizontal line, with each later generation placed below 

 the next earlier. Male individuals are indicated by squares, females 

 by circles, suspended by vertical lines (individual lines) from the 

 horizontal line. Members of one fraternity are connected by the same 

 horizontal line. The rank of birth in the fraternity is indicated by a 

 serial number placed immediately above the fraternity line. When 

 the sex is unknown the square or circle is omitted from the end of the 

 individual line. The fraternity line is connected by a vertical line 

 (descent line) to a line joining the symbols of father and mother 

 (mating line). The mating line may be a short horizontal one or 

 oblique, passing from one consort to the other as emergencies of space 

 decide. Dotted mating lines are used for illegal unions. When a 

 marriage of one of the individuals of a fraternity who occupies a 

 middle position in the series is to be represented, the consort is placed 

 below and to the right or left of the circle or square and joined to it 

 by an oblique line from which is dropped a descent line meeting the 

 fraternity line. In the case of illegitimate children, the descent line 

 is dotted. 



For purposes of reference from description to chart each sheet 

 of a pedigree is numbered serially with Arabic numerals. On each 

 sheet the generations are numbered serially at the left margin with 

 Roman numerals (I, II, III, etc.) beginning with the oldest generation. 

 In each generation each individual symbol is numbered with Arabic 

 numerals from left to right. In the text reference is made to an 

 individual on the chart by sheet, generation and individual number. 

 Thus 1, II, 17 means the first sheet, II generation, 17th individual 

 symbol from the left. For the sake of uniformity in charting the 

 families, the paternal side of the family is placed at the left of the 

 chart, the maternal side at the right. 



(For display charts. As a matter of convenience and as an aid 

 in tracing the patient's immediate family, showing at a glance the lines 

 of paternal and maternal descent of the defect, the descent line con- 

 necting the paternal side may be made green. Red may be used for 



