180 NATURAL INHERITANCE. [CHAP. 



power of the mother over that of the father to produce 

 a highly consumptive family. Aiiy physician in large 

 practice among consumptive cases could test the ques- 

 tion easily by reference to his note-books. A " highly 

 consumptive " fraternity may conveniently be defined 

 as one in which at least half of its members have 

 actually died of consumption, or else are so stricken 

 that their ultimate deaths from that disease may be 

 reckoned upon. Also to avoid statistical accidents, the 

 fraternities selected for the inquiry should be large, 

 consisting say of six children and upwards. Of course 

 the numerical proportions given by the above 1 4 frater- 

 nities are very rude indications indeed of the results to 

 which a thorough inquiry might be expected to lead. 



Accepting the general truth of the observation 

 that consumptive mothers produce highly consumptive 

 families much more commonly than consumptive fathers, 

 it is easy to offer what seems to be an adequate ex- 

 planation. Consumption is partly acquired by some 

 form of contagion or infection, and is partly an here- 

 ditary malformation. So far as it is due to the latter 

 in the wide sense already given to the word " mal- 

 formation," it may perhaps be transmissible equally by 

 either parent. But so far as it is contagious or 

 infectious, we must recollect that the child is pecu- 

 liarly exposed during all the time of its existence 

 before birth, to contagion from its mother. Daring 

 infancy, it lies perhaps for hours daily in its mother's 

 arms, and afterwards lives much by her side, closely 

 caressed, and breathing the tainted air of her sheltered 



