236 
THE HEART-BEAT. 
The explanation I am going to suggest will seem to some 
no explanation at all. It is this : that the heart beats because 
it inherits the power of beating ; that as an animal transmits to 
its offspring its form and instincts, so it hands down this power 
of rhythmical contraction of the heart. It is a question of 
inheritance. We inherit a limited life, and a heart whose power 
is also limited. Nay, more ; the heart of an animal always begins 
to beat at the same time as its parent’s did before it. If you put 
a hen’s egg into a warm, uniform temperature for a couple of 
days and then carefully chip off the shell, you will see, lying 
upon the yolk, a small, red, palpitating spot, which is the future 
heart. I say future, because as yet the heart is merely a mass' 
of cells, hollowed out in the centre, and has neither muscle nor 
nerve in its walls. Yet it beats regularly and always begins at 
about the same time — towards the end of the second day of 
incubation — because its father’s did before it. This great 
principle of inheritance, the most important law in the organic 
world, is no mean explanation of the heart-beat, although at 
first it seems ridiculously simple. How that movement originated 
ages ago we are not concerned with now. 
The reason of the regular 7'hythm of the heart-beat is also 
unknown ; but we notice, as Dr. Michael Foster has observed, 
that rhythm is the order of the Universe. The moon and the 
earth and other planets have stated intervals in which to 
revolve ; our brains have alternately periods of rest and activity ; 
the lives of men and all other animals have fixed durations, 
beyond which they cannot go. They gather strength, beat, and 
cease, as the heart gathers strength, contracts, and lies quiet 
until the next pulsation. The heart,” says Foster, “ is the 
reflex, in little, of the cycles of the Universe.’' 
