6 
THE YOUNa SCIENTIST. 
parasite, the Trichodina pediculus, (which 
will be shown further on), and it must 
happen that either this visitation is not 
disagreeable, or that the Trichodina is not 
influenced by the poison. 
As the plants in the bottles decayed, 
some of the animalcules died off and 
others appeared. In one bottle, contain- 
ing decaying chara, Faramecia abounded. 
The Faramecia, of which there are various 
species, have always been favorite objects 
with microscopists. The Germans call 
them "slipper animalcules," and they 
vary in size from 1—96"* to 1—1150". They 
are flat rounded-oblong creatures, with a 
distinct integument or skin, " through 
which numerous vibratile cilia pass in 
regular rows."t They are furnished with 
a distinct mouth, and adult specimens 
exhibit star-shaped contractile vesicles in 
great perfection. 
The swarm of specimens before us be- 
long to one species, Farameciuni aurelia, 
the Chrysalis animalcule, and they crowd 
every portion of the little water-drop we 
have taken up, and examined with a power 
of about one hundred linear. "When they 
are sufficiently quiet a power of about four 
hundred may be used with advantage, and 
Pritchard recommends adding a little 
indigo and carmine to the water, in order 
to see the cilia more clearly, or rather to 
render their action more plain. The cilia 
are disposed lengthwise, and Ehrenberg 
Paramecium aurelia. 
A dried specimen showing the vesicles. 
Fritchard. 
counted in some rows sixty or seventy of 
them, making an aggregate of three thou- 
sand six hundred and forty organs of 
motion in one small animated speck. This 
number seems large, but although we 
have never performed the feat of counting 
them, we should have expected it to prove 
much greater. Unlike most animalcules 
they are susceptible of being preserved by 
drying upon glass, and we subjoin a figure 
from Pritchard, of one thus treated, in 
which the star-shaped vesicles are clearly 
seen. These curious organs communicate 
* The usual mode of giving dimensions is by 
fractions thus expressed: 1—96" means one 
ninety-sixth of an inch. 
t ' Micrographic Dictionary.' 
with other vessels, and, as we have pre- 
viously stated, are probably connected 
with respiration and excretion. 
The genus Faramecium is now confined 
to those creatures which exhibit rows of 
longitudinal cilia of uniform length, which 
are destitute of hooks, styles, or other 
organs of motion than the cilia, which 
have a lateral mouth, and no eye-spots. 
One mode of increase is by division, which 
may be easily observed ; another is 
through the formation of true eggs as 
traced by Balbiani. 
Another of the treasures from the pond 
was a species of TracUelius^ or long-necked 
ciliated animalcule, which kept darting in 
and out of a slimy den, attached to the 
leaf of a water-plant. The body was stout 
and fish-shaped, the tail blunt, and the 
neck furnished with long conspicuous 
cilia, which enabled the advancing and 
retreating movements to be made with 
great rapidity. The motions of this 
creature exhibit more appearance of pur- 
pose and design than is common with 
animalcules, but in proportion as these 
observations are prolonged, the student 
will be impressed with the difficulty of 
assuming that anything like a reasoning 
faculty and volition, is proved by move- 
ments that bear some resemblance to 
those of higher animals, whose cerebral 
capacities are beyond a doubt. It is, how- 
ever, almost impossible to witness motions 
which are neither constant nor periodic, 
without fancying them to be dictated by 
some sort of intelligence. We must, 
nevertheless, be cautious, Jest we allow 
ourselves to be deceived by reasoning so 
seductive, as the vital operations of the 
lowest organisms may be merely illustra- 
tions of blind obedience to stimuli, in 
which category we must reckon food, and 
until we arrive at forms of being which 
clearly possess a ganglionic system, we 
have no certainty that a real will exists, 
even of the simplest kind ; and perhaps 
we must go still higher before we ought 
to believe in its presence. 
Ehrenberg was much struck with the 
restless character of many infusoria — 
whether he looked at them'by day or by 
night, they were never still, in fact. their 
motions are like the involuntary actions 
which take place in the human frame; 
and if attached to their bodies we observe 
cilia that never sleep, the living membrane 
of some of our own organs, the nose, for 
example, is similarly ciliated, and keeps 
up a perpetual though unconscious work. 
The Faramecia increase and multiply 
their kind without any fear lest the due 
adjustment between population and food 
should fail to be preserved. A small drop 
of the scum from the surface of the water 
in their bottle is an astounding sight. 
They move hither and thither in countless 
numbers, seldom jostling, although thick 
