244 



THE 



AIUHALIST 



[Vol. LI 



to the same organ by different diseases, or to different organs by 

 different diseases — have been worked out. Only 4 of these — 

 that is only about one case out of six — are exceptions to the rule 

 that varieties which show more than the average amount of 

 injury by one disease will, on the whole, show more than the 

 average injury by another disease. No one of these exceptional 

 constants can be considered significant with regard to its prob- 

 able error. Several of the 19 which indicate the rule may be 

 looked upon as individually trustworthy. Thus notwithstanding 

 the large variations in numerical magnitude incident to small 

 series of data and rough measurement, the determinations taken 

 collectively certainly furnish highly convincing evidence that to 

 a considerable extent susceptibility to disease is general rather 

 than specific. 



The fact that the series of correlation coefficients here pre- 

 sented justify much more definite conclusions than those who 

 have considered the data without statistical analysis have drawn, 

 is sufficient indication of the usefulness of the biometric method 



which large nunibors of strains are being tested, and in which 

 the mass of data is highly confusing. The special cases illus- 

 trated by no means oxliausf the possibilities of the biometric 

 formula^ now avaihililo. Had tlio data been more extensive, the 

 analysis mi^^lit liavo been cai-i'ied much farther. 



statistical mctliod innst bi' taken to imply that the most careful 

 individnal analysis is not (lesira])Ie and essential. The two 



J. AirnTUR Harris 



THE DIFFERENT MEANINGS OF THE TERM "FACTOR" 

 AS AFFECTING CLEARNESS IN GENETIC 

 DISCUSSION^ 



