Other evidence as to the relative influence of heredity and training, which Goring suggests, is in connection with the difference in influence of the two parents. If the contagion were from either the mother or father alone, the difference in resemblance to that parent and the other might indicate the strength of the contagion. The difference amounts to about .05. This again, in his opinion, gives some idea of the relative importance of nature and nurture within the family. The measure would not be complete unless the hereditary tendency to resemble mother and father were equal and the contagion were all from one parent. Husbands and wives tend strongly to resemble each other in crime, the correlation being .6378. This resemblance is of course not due to heredity. Goring believes that it is not due to contagion and argues that besides the subjective tendency for the criminals to associate together, there is here a large element of conscious choice of a mate among the criminal classes, especially as the criminal woman shows the tendency most clearly and would not be able easily to get a non-criminal husband. This work of Goring illustrates how an important beginning has been made in applying the correlation method to objective records, in order to weigh the relative importance of hereditary and environmental sources of crime. Perhaps its most important support is the close agreement between his conclusions as to the importance of the native diathesis of criminality and other studies by the biometric school as to the family tendencies in physical traits such as stature, eye color, tuberculosis, insanity, and deafness. These all tend to show a correlation between parents and children or brothers and sisters of about .5 as compared with relations to environmental factors which tend to be less than .1 (_165_). (d) THE CRIMINAL DIATHESIS.