174 



NATURAL INHERITANCE. 



[chap. 



consumptive taint of each fraternity. For instance, if 

 in a fraternity of 10 members there was one actually 

 consumptive member and four "somewhat suspiciously" 

 so, it would count as a fraternity of ten members, of 

 whom two were actually consumptive, and the average 

 taint of the fraternity would be reckoned at one-fifth 

 part of the whole or as 20 per cent. 



Treating each fraternity separately in this way, and 

 then averaging the whole of them, the mean taint of 

 the children of one consumptive parent was made out 

 to be 28 per cent. 



Distribution of Fraternities. — Next I arranged the 

 fraternities in such way as would show whether, if we 

 reckoned each fraternity as a unit, their respective 

 amounts of consumptive taint were distributed " nor- 

 mally " or not. The results are contained in line A of 

 the following table : — 



Percentage of Cases' having various Percentages of Taint. 





Percentages of Taint. 







and 



under 



9 



10 



and 



under 



19 



20 



and 



under 



29 



30 

 and 



under 

 39 



40 

 and 



above 



Total. 



A. 66 cases, one 

 parent con- 

 sumptive. 



27 



20 



9 



15 



29 



100 



B. 84 cases, one 

 brother con- 

 sumptive. 



49 



14 



10 



13 



14 



100 



