i«89.] Days ajtd Nights by the Sea. 415 
of the higher animal with its marvellous organs, the eye, the 
heart and brain from the egg cell. If the eye or the brain is com- 
plicated, what must we say of this unicellular germ, the &gg, 
in which in large measure certainly, the adult structure must 
potentially exist. 
Some may think that since the young of different animals 
are subjected to peculiar conditions, to varying climate, food 
and the like, their differences in structure may be influenced 
by their surroundings. But this objection is easily answered, 
for we can rear the eggs of such diverse forms as the fish, the 
sea urchin, and the oyster in the same tumbler of water, where 
the conditions are identical. We are thus brought face to face 
with the great problem of heredity, that is, the law by which all 
living things tend to resemble the parents from which they 
sprung, or some ancestor belonging to their immediate race, 
in spite of variability or adaptation to environment. That the 
coral polyp reaches a certain stage of development and stops, 
that the starfish travels by this same road but advances far 
beyond, the young always coming to resemble the adult ; that 
the higher animals pass still farther along this path ; that the 
child resembles its parents often to a trick of speech or to a 
shade of mental or moral character, or that sometimes the char- 
acter of a preceding generation makes its appearance, is one 
of the most remarkable phenomena which man has observed. 
Marvellous as it is, it seems not to be inscrutable, and the studies 
of recent years are lightening its dark passages. 
It may be asked, of what use is the knowledge of the struc- 
ture and development of animals below man. The chief aim 
in natural science is to discover relations. The life history of 
a coral is valuable for the light it throws on the problem of all 
0'*ganic life. The great laws governing all living matter are the 
same. VVe can only read the complex through the simple. The 
lower we pass in the scale of animal and plant life, the simpler the 
structure, the more nearly are the problems reduced to lowest 
terms. 
The most interesting object in nature is man, and apart from 
the high claims of pure science, of knowledge for its own merit. 
