Vol. XXIV. No. i.] 
POPULAR SCIENCE I^EWS. 
[Original in The Popular Science N ws.] 
BRIEF STUDIES IN BIOLOGY. 
BY PROF. JAMES H. STOLLER. 
I. 
THE AMrF.BA. 
The delightful field ot knowledge which modern 
biology has opened, has scarcely yet been explored 
by the intelligent general reader, so recently has it 
been added to the realm of science. It is therefore 
believed that a series of brief studies, which may 
serve to guide the reader to an apprehension of the 
leading facts and principles of the science of life, as 
known at the present day, may be acceptable to 
many. Our method will be to study a number of 
forms of animal life, seeking to find out how they 
illustrate, in the forms of their bodies and the carry- 
ing on of their life processes, the laws which govern 
the world of animate nature. Naturally, we shall 
begin with the simplest of organic beings, and pro- 
ceed in order toward the highest forms. 
What, then, is the simplest form of animal life.' 
The word which stands at the head of this article is 
the name of a typical unicellular animal, found 
everywhere in pools of stagnant water, which biolo- 
gists commonly refer to as a representative of the 
lowest class of animal organisms, viz. : the Protozoa. 
The amceba is a very tiny creature, visible only by 
the aid of the microscope. But it is so simple in 
structure that one can get quite a correct idea of it 
from a description. Imagine how a bit of uncooked 
white of egg, spread out flat and of an irregularly 
rounded form, would look, and you have a very 
good notion of the appearance of the amoeba under 
the microscope. And a notion obtained in this way 
is not only correct as to the appearance of the organ- 
ism, but also as to the nature of the material of 
which the body is made. For the albumen of which 
white of egg consists, in its chemical and physical 
properties is precisely similar to that substance, 
called protoplasm, which composes the bodies of 
the protozoan animals. 
But let us stop here to note a very important dis- 
tinction : If a bit of white of egg be left to itself, in 
a little while it wastes away; the oxygen of the air 
attacks it and converts it into new compounds. 
But if an amoeba be left to itself, under natural con- 
ditions, it does not undergo destructive change; it 
is endowed with a principle of life, by which it can 
resist the attacks of the oxygen. Thus, while the 
amceba, when subjected to the chemist's analysis, is 
found to consist of the same chemical elements as 
white of egg, — namely: carbon, oxygen, hydrogen, 
and nitrogen, — it also possesses, in addition to this, 
a something else- — a something which enables it to 
maintain itself intact against external physical 
forces. This something is life. We may sav that 
it is a force resident in the protoplasm of which the 
body of the organism consists. It is as well to call 
it the vital force, and to correlate it with the physi- 
cal forces, heat, electricity, magnetism, etc. And 
just as we do not know the real nature of these 
physical forces, but know them only by their mani- 
festations, so we do not know the real nature of life, 
and can only say that it manifests itself by certain 
phenomena, happening in more or less certain 
order, — that is to say, according to laws more or 
less known to us. The study of biology is the studv 
of the laws which govern the phenomena manifested 
by living bodies. 
Let us now return to the amoeba, understanding 
that the task before us is to observe and reflect upon 
the phenomena which it manifests. By watching a 
little while, one is sure to observe a change in the 
form of the body taking place. There is a thrusting 
out of one side into a club-like projection ; presently 
the rest of the body, by a kind of flowing motion, 
moves toward this projection. The animal is able 
to push out any side of its body in this way, so that 
when it wishes to change its direction it has no 
need to turn about, as those animals do which 
always move with one end forwards. These pro- 
jections are called pseudopodia, a word which means 
false feet; they are organs of locomotion, but, as 
they are formed for only temporary use, it is no 
more than right that their pseudo character should 
thus be recognized in their name. As the creature 
is moving about in this way, it may chance to come 
in contact with a particle of matter which it can use 
for food. If so, it immediately proceeds to swallow 
it. But, as the organism has no mouth nor stoinach, 
— being only a bit of structureless homogeneous 
protoplasm, saving a central portion called the 
nucleus, — it must improvise a digestive cavity as 
occasion demands, just as it improvises feet when it 
wishes to move. It simply flows round the particle 
until it is completely enclosed in its body-substance, 
where it then undergoes digestion. Beyond doubt, 
the amceba digests and assimilates its food — in other 
words, performs the general function of nutrition — 
just as perfectly as the higher animals do, though 
destitute of any special organs for carrying out this 
function. Its food is of just the same nature as that 
of the higher animals, consisting of organic matter, 
such as minute plant cells, and water. It takes this 
food into its body and converts it into its own sub- 
stance (assimilates.) As a result of this process, 
the amceba shows increase of size, or growth. The 
facts at hand, then, are that the simplest animal 
organisms are able to procure food, to swallow, 
digest, and assimilate it, thus effecting growth and 
maintaining life, just as perfectly as the most highly 
organized animals. When it is called to mind that 
in the higher animals, as in man, there are several 
systems of organs — the digestive, the circulatory, 
and the excretory — which are subservient to the 
function of nutrition, it is seen that the problems of 
physiology, instead of being rendered simpler in the 
lowest organisms, are really more difficult to under- 
stand. We can only say that the protoplasm which 
constitutes the body of the amoeba is able of itself 
to perform the functions of the stomach, heart 
kidneys, etc., of the higher animals. 
Having thus seen that the amoeba is able to per- 
fectly discharge the physiological function of 
nutrition, — the function by which it is kept alive as 
an individual being, — let us now find out whether it 
is able to discharge the other fundamental function 
of living bodies, namely, reproduction — that by 
which its kind, or species, is kept alive. By patient 
watching it will be found that any amreba, after a 
greater or less length of time, undergoes division of 
its body into two parts. It is as if an invisible thread 
was passed around the body, and the loop drawn 
smaller and smaller, until the body was constricted 
into two. Each of these parts has all the powers of 
the being from which they were formed ; they are, 
in fact, a new generation of amcebas. Each is 
destined to grow to its full size, to nourish itself for 
a while, and then, in turn, by the simple process of 
self-division, to give rise to a new generation of its 
kind. Thus, by the simplest process we are able to 
think of, the function of reproduction — fundamental 
to all living beings — is effected. 
The manifestations of life seen in a study of the 
amceba may therefore be summarized as follows : 
(i) power of self-movement; (2) power of taking in 
outside matter as food and converting it into its own 
substance; (3) power of reproducing its kind. 
This sketch of a typical organism of the lowest 
grade in the scale of life would not be complete if it 
was not pointed out that the amceba is exactly simi- 
lar to certain cells found in bodies of all the higher 
animals, including num. It is well known that the 
blood consists of a liquid plasma in which float cor- 
puscles of two kinds, the red and white. Now the 
white corpuscles are almost precisely like amcebas. 
Like them, they consist of minute masses of proto- 
plasm, containing in their central part a nucleus ; 
and, like them, they are constantly undergoing 
changes of form. It is also highly probable that 
they nourish and reproduce themselves, just as 
amcebas do; at any rate, this affirmation can be 
made of other cells, especially during the embryonic 
period of life. 
In this connection it is instructive to draw this 
parallel : Of all the forms of animal life, the amoeba 
is the simplest, retaining with the least modification 
the properties of the elementary form of living 
matter, viz. : protoplasm. So, likewise, of all the 
cells of the body, the white corpuscles are the least 
specialized ; unlike the cells which go to make the 
nerves, muscles, and bones, they have not acquired 
special distinctive qualities, but retain in the least 
degree modified, the properties of elementary living 
matter. In other words, the amoeba stands at the 
bottom in the scale of animal life, and the white 
corpuscles, and other simple cells, stand at the 
bottom in the scale of the structural elements that 
go to make up the body. 
Union College, Schenectady, N. Y. 
[Original in The Popular Science Neici.l 
FAUNA AND FLORA OF PRIMITIVE AND 
RECENT PERIODS. 
BY JOSEPH WALLACE. 
It is singularly strange, in this age of progress 
i.nd advanced science, to find some people who call 
themselves learned still persisting that the present 
fauna and flora are but pigmies in comparison to 
those which are extinct. Thanks to the advance- 
ment in paleontological researches, we know the 
former and present fauna and flora, for it teaches us 
about the animals and plants which have existed on 
the earth, but, for the most part, do not at present 
exist. The history of the present fauna and flora is 
a supplement or revised edition of the history of the 
fauna and flora of the primeval world ; no visible 
signs of a universal catastrophe of animal and vege- 
table life can be traced. The most marked change 
on the earth's surface took place at the close of the 
Mesozoic or Secondary period, when lycopods, 
ferns, cycads, and yew-like conifers passed away, 
and diocotyledonous angiosperms — the hard-wood 
trees and evergreens of today — succeeded them, but 
not by any sudden extinction, for some of these 
trees had already begun to make their appearance 
in Cretaceous times. Consequently, natural history 
is complete, because it embraces two classes of 
organic beings : those which still exist and those 
which are extinct. 
It seems natural in man to be imaginative and 
susceptible of wild, grotesque, and fabulous impres- 
sions of pre-existing organic forms. No doubt, 
primeval plants and animals of odd and rare descrip- 
tion are found, but it is by no means generally the 
case. Strange forms occur among petrified remains, 
as in the case of reptiles. Among these are found 
various saurians, or species of flying and swimming 
lizards, as the plesiosaurus and peterodactylus; 
among the mammalia, the dinotherium giganteum. 
But strange forms also exist at the present day ; for 
instance, the ornithorhynchus, ant-eater, sloth, and 
flying-dragon ; and, as a rule, those were just as 
rare formerly as these are now. The same holds 
good in regard to size of the organisms. The 
present equisetacea;, or horse-tails, are usually a 
foot high (seldom exceeding four feet), and about 
the thickness of one's thumb ; our lycopodiacei, or 
mosses, consist of tendrils with thin, branching 
stems, which wind along the ground between the 
