AND ENVIRONMENT II 



husband and wife has been selected because they were 

 parents of at least one tuberculous child. If the view 

 be held that tuberculosis is not hereditary, then although 

 we have selected the parents of tuberculous children 

 we should not very much increase the value just found, 

 for the infection factor would only be of the order 0-17 

 (between parent and child also). But if we accept the 

 hereditary factor, then the correction needful will send 

 up the relationship between husband and wife to some- 

 thing like 0-30. These results as a whole seem to indicate 

 that the average value of the correlation in phthisis 

 between husband and wife must lie between 020 and 

 0-30, but that it decreases as we pass from the more highly 

 educated to the lower classes. 



We have to seek an explanation of this matter, and 

 the first light we can throw on it is to find the resem- 

 blance of husband and wife in other characters than 

 tuberculosis. I take the extremes : first, insanity, 

 where we cannot imagine any infective relation, and 

 then alcoholism, where we might suppose mutual in- 

 fluence to be great. In Table V we see the remarkable 

 fact that the number of pairs of insane husbands with 

 insane wives is more than double their chance frequency. 

 The correlation of insanity in husband and wife is 0-24, 

 exactly what we found for tuberculosis in material also 

 drawn from the professional classes. In this table for 

 insanity I have included among the insane some indi- 

 viduals having night terrors, or markedly neurotic. If 

 these be included with the normal, the correlation rises 

 to 0-30, or appears as large as the average value of 

 Pope's data for tuberculosis. I now turn to alcoholism 

 as obtained by Dr. Goring for upwards of 1,400 cases. 

 Instead of a transfer of 14 individuals in the 1,000 we now 



