402 Notices of Books. [July, 
The following passage is of profound significance :—‘‘ Children 
born of parents one or both of whom are between 25 and 40 are, 
on the average, stronger and smarter than those born of parents 
one or both of whom are much younger or older than this.” 
Political economists, we believe, claim the privilege of being 
ignorant of every science except their own, and in virtue of that 
ignorance they counsel late marriages, in the hope of checking 
the too rapid increase of population. Unfortunately their scheme 
reduces not merely the number, but the stamina, physical and 
mental, of a nation. 
Dr. Beard next examines the moral faculties, and finds them 
subject to the same law. “It does not follow,” says he, ‘ that 
when a man declines in moral principle that he necessarily be- 
comes a horse-thief—a loss of active moral enthusiasm is fre- 
quently all that is noticed.”” Among the causes of moral decline 
in old age the author enumerates—‘‘ Over-exercise through life 
of the lower at the expense of the higher nature; disease of the 
brain, or of other parts of the body that react upon the brain, 
and intellectual decline.” ‘‘ Death,’ he remarks, ‘‘is more fre- 
quently a process than an event. When conscience is gone the 
constitution may soon follow.” In illustration of the decline of 
the moral faculties in old age, we are referred to the lives of a 
number of historical characters, among whom figure the names 
of Carlyle and Ruskin. A note on the death of Agassiz must 
not be overlooked :—‘‘ To his friends it is well known that 
Agassiz began to die several years ago. His death can be hardly 
regarded as a loss to scientific research, for he had long ceased 
to be productive. So far as he lives in the future of science, it 
will be mainly for the original work that he did before he reached 
his fortieth year. The intemperate manner of his opposition to 
the theory of evolution, by which he was so rapidly winning 
favour among the thoughtless and ignorant, and so rapidly losing 
favour among the conscientious and scholarly, may find its par- 
tial—if not complete—explanation in the exhausted condition of 
his brain.” 
We are here reminded of those changes of opinion on contro- 
verted points—theological, political, or philosophical—which 
eminent men sometimes experience in the decline of life. The 
old friends of such a character seldom fail to denounce him as a 
pervert and a renegade, and to accuse him of corrupt motives. 
Those whom he has just joined hail him a convert, and rejoice 
that his eyes have at last been opened to the truth. Both are 
wrong. Such changes are often sincere, but they spring not 
from illumination, but from a darkening of mental vision. The 
accession of a man, once great, who has fallen into second 
childhood, is no great triumph to any party. What matters it if, 
in his declining years, Liebig showed leanings to Obscurantism ? 
One of the most ordinary phases of mental decay is the mingled 
incapacity and unwillingness to recognise new discoveries or new 
