every week from severe headaches, which were relieved only by a recumbent
position in a dark room. Their father, paternal uncles, paternal grandfather,
and granduncles all suffered in the same way from headaches, which ceased at
the age of fifty-four or fifty-five in all those who lived so long. None of
the females of the family were affected. (14/44. These cases are given by Mr.
Sedgwick on the authority of Dr. H. Stewart in 'Med.-Chirurg. Review' April
1863 pages 449, 477.)]

It is impossible to read the foregoing accounts, and the many others which
have been recorded, of diseases coming on during three or even more
generations in several members of the same family at the same age, especially
in the case of rare affections in which the coincidence cannot be attributed
to chance, and to doubt that there is a strong tendency to inheritance in
disease at corresponding periods of life. When the rule fails, the disease is
apt to come on earlier in the child than in the parent; the exceptions in the
other direction being very much rarer. Dr. Lucas (14/45. 'Hered. Nat.' tome 2
page 852.) alludes to several cases of inherited diseases coming on at an
earlier period. I have already given one striking instance with blindness
during three generations; and Mr. Bowman remarks that this frequently occurs
with cataract. With cancer there seems to be a peculiar liability to earlier
inheritance: Sir J. Paget, who has particularly attended to this subject, and
tabulated a large number of cases, informs me that he believes that in nine
cases out of ten the later generation suffers from the disease at an earlier
period than the previous generation. He adds, "In the instances in which the
opposite relation holds, and the members of later generations have cancer at a
later age than their predecessors, I think it will be found that the non-
cancerous parents have lived to extreme old ages." So that the longevity of a
non-affected parent seems to have the power of influencing the fatal period in
the offspring; and we thus apparently get another element of complexity in
inheritance.