HEREDITY IN PHYSIOLOGY, IN MEDICINE, 
AND IN PSYCHOLOGY. 
THERE are many grounds of pride and satisfaction for 
the mind in the sciences known to man, but reasons for hu- 
mility and bitter regret are also supplied by them to the 
full. Spite of the persistent strivings and labored medita- 
tions of the legions of investigators who have gone before 
us, Nature still has her deep and dark abysses, at whose 
blank look all insight turns to blindness, all boldness dies 
in fear, and all confidence becomes despair. When we at- 
tempt to throw a little light upon the heart of these mys- 
terious chasms, that light merely reflects to our view the 
ghosts of our own ignorance, and we gain from the futile 
effort only a fresh conviction of our own impotence and 
poverty. It would be wise to gain from it something 
more ; I mean, a lesson to benefit us. Indeed, nothing 
should so chide us back to humility and patience, so cool 
our presuming eagerness and daunt our daring arrogance, 
as the study of those phenomena which Providence seems 
to have ordained purposely to baffle buman inquisitiveness. 
Yet many men affect to be unconscious of the astounding 
and intricate operations which are taking place in regions 
that sight and sense never sound, and stubbornly dispute 
the existence of unseen activities and unfelt powers. This 
is the deadly, doubting temper that the evidence of those 
sphinxes of which we are now treating must be brought 
to attack. The lesson is all the more eloquent because, by 
strange contrast, those questions that defy every kind of 
