378 Boas AlN: 
The symptom of the disease is that the blood refuses to clot, and hence 
there is great loss of blood from even a very slight wound, such as a 
scratch. The peculiarity about its inheritance is that only the male 
members of a family are affected, but the disease is usually transmitted 
through the females, who do not themselves develop it. An apparently 
healthy daughter belonging to such a family will transmit the affection 
to her sons, and her daughters will be capable of handing it on to their 
children. 
If we pass from a consideration of man’s physical nature and ask our- 
selves whether and to what extent the principles we have been discussing 
are applicable to his moral and intellectual qualities, we enter a field of 
speculation of the very highest interest. In his work on * Hereditary 
Genius,’ published in 1869, Francis Galton brought together and analysed 
a great mass of information which proved conclusively that excellence in 
many intellectual and moral qualities occurred in particular families with 
a frequency out of all proportion to that in which it was found in the 
general population. No one will, I think, dispute the fact that musical 
ability is inherited in certain families, and the same seems to be true of 
mathematical genius, though by no means all the nearly related members 
of the families possess the exceptional powers. Galton gives a list of 
36 men who took the place of senior classic at Cambridge between 1824 
and 1869. In this list of 36, the name Kennedy occurs four times, three 
of the men being brothers and the fourth a nephew of the others. The 
name Lushmgton occurs twice, the men being brothers, whilst a third 
brother was fourth classic of his year. 
Mendel’s law was unknown to Galton when this book was written, but 
a consideration of his data certainly suggests that some at least of the 
exceptional mental and moral attributes with which he deals may follow 
the general principles of inheritance which Mendel first made clear. The 
question is one which may well repay further investigation. And if the 
future should reveal to us with certainty the fundamental principles ac- 
cording to which human qualities, both physical and mental, are handed 
on from generation to generation, shall we not have reached a real land- 
mark in the progress of the human race towards well-being ? It is not 
that one contemplates direct interference with the liberty of the in- 
dividual, excepting perhaps in extreme cases of physical or mental 
disease, but we may, I believe, look forward to a gradual incorporation 
in the traditions and social usages of the people, of such knowledge as 
shall come to stand on a certain and indisputable scientific basis. The 
immense power of such traditions and customs on the life of the general 
population cannot be denied. Gradually, too, as the new facts become 
firmly established, religious teachers will lend their aid, and ethical 
