Page 90 - My FlipBook

teni. Here, then, we have the apparatus reduced to a simple
straight tube with a sahvary gland, and numerous minute
glands representing the liver. With this apparatus the earth
worm is enabled to digest and take out its food from the
earth, which it takes into itself. It seems simply to take in
the earth in which it lives, and in that earth it gets its sub-
sistence. And if any of you want nice, fat fishing worms put
them in a can of earth and give them a little milk every day
or two and you will find they will grow splendidly.
Now we may go one step lower still, or go to the lowest
point of animal life—the amoeba. Here we find nothing but
—
a simple globule of protoplasm ; it has no organs whatever
a simple, naked cell. In its globular form it may be repre-
sented like this (making drawing on board) just simply as a
globule, microscopic in size. Yet, this little animal manages
to walk about, capture its food, digest and appropriate it. I
suppose you have studied the amoeba sufficiently to under-
stand the amoeboid movement. For instance, if we have a
globule here (indicating) the material begins to run out here
and runs into that, and in that way it passes from one point
to another. Then it will begin to run out here and run into
that and pass to that point. And if it meets with a particle
in its way it will simply surround it and take it into itself,

and in that way it forms a stomach for the occasion, digests
that particle of food, and if there is a particle that is un-
digestible it will walk away and leave that undigested por-
tion in its track, but has appropriated the digestible part of
the particle of food. In that way it walks about, captures its
prey, performs the act of digestion and nutrition, perform-
ing these two functions the same as the higher animals.
Then the organs are simply a provision for the more perfect
accomplishment of these results—they are not absolutely
necessary to it.

Waste Products.
The functions of absorption and nutrition do not go on
continuously without the other function of denutrition, or the
function of the formation of waste products. If the kidneys
fail to act, if the urea is not eliminated from the blood, the
man dies. This function of the elimination of waste products
is as important to life as the function of nutrition : indeed,

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