68 
THE YOUNG SCIENTIST. 
The gizzard of this family (Philodinoea) 
presents a considerable deviation from 
the perfect form exhibited by the Bra- 
•chions. According to Mr. Gosse, " The 
mallei and the incus (terms already ex- 
plained) are soldered together into two 
subquadrantic-globular masses, which 
appear to be muscular, but invested 
with a solid integument. The manubria 
(handles) may still be recognize i in a 
vertical aspect as three loops, of which 
the central one is chiefly developed, and 
In a vertical aspect as a translucent reni- 
form (kidney-shaped) globe." These de- 
scriptions are not easy to understand, not 
from any want of clearness or precision in 
the words employed, but from the com- 
plicated character of the organ, and its 
very different appearance under different 
aspects. To make the matter more intel- 
ligible, Mr. Gosse adds, "the structure and 
action of an apparatus of this type may 
be made more clear by a homely illustra- 
tion. Suppose an apple to be divided 
longitudinally, leaving the stalk attached 
to one half. Let this now be split again 
longitudinally so far as the stalk, but not 
actually separating either })ortion from 
it. Draw the two portions slightly apart, 
and lay them down on their rounded 
surfaces. They now represent the quad- 
rantic masses in repose, the stalk being 
the fulcrum, and the u])per surfaces being- 
crossed by the teeth. By the contraction 
of the muscles, of which they are com- 
posed, the two segments are made to turn 
upon their long axis, until the jjoints of 
the teeth are brought into contact, and 
the toothed surfaces rise and approach 
each other. The lower edges do not, 
however, separate as tlie upper edges ap- 
proach, but the form of the mass alters, 
becoming more lenticular, so that when 
the toothed surfaces are brought into 
their closest ai^proximation, the outline 
has a subcircular figure. It is on account 
of this change of form that I presume 
the masses themselves to be partially 
composed of muscle." 
These remarks, although si^ecially 
made of the Rotifer wacTiirus, are in the 
main ai^plicable to all the Philodinas, 
"but the student must not expect to under- 
stand any of the complicated gizzards of 
the rotifers without repeated observa- 
tions, and no small exercise of patience. 
It is common to call the portions of 
the Philodine-pattern gizzard "stirrup- 
shaped," but Mr. Gosse has shown them 
to be qnadrcudic, that is, shaped like the 
quarter of a sphere. 
As we are not very well off with sub- 
jects for description at present, we can 
afford a little time to consider a question 
that continually arises in the mind on 
viewing the movements of animalcules, 
and especially of any so highly developed 
as the rotifers, namely, to what extent 
motions which appear intelligent are 
really the result of anything like a con- 
scious purpose or will. When any of the 
lower animals — a bee, for example — acts 
in precisely the same way as all bees have 
acted since their proceedings have been ob- 
served, we settle the question by the use of 
the term instinct. Those who take the low- 
est view of insect life, assume that the bee 
flies because it has wings, but without 
wishing to use them, and that the nerves 
exciting them to action are in their turn 
excited, not by volition, but by some 
physical stimulus. 
The sight or the smell of flowers is 
thought by the same reasoners to be ca- 
pable of attracting the insect, which is 
unconscious of the attraction, while prox- 
imity of food stimulates the tongue to 
make the movements needful for its ac- 
quisition, and so forth. The cells, they 
tell us, are built according to a pattern 
which the earliest bee was impelled to 
construct by forces that bear no analogy 
to human reason and human will, and so 
originate all the ordinary processes of 
bee life. Sometimes, however, it happens 
that man or accident interposes particular 
obstacles, and forthwith there appears a 
particular modification of the orthodox 
plan, calculated to meet the special diffi- 
culty. How is this ? Does any one of 
the difficulties which the bee or the ant 
is able to get over, produce precisely that 
kind of electrical disturbance, or polar 
arrangement of nerve particles that is 
necessary to stimulate the first step of 
the action by which the difficulty is sur- 
mounted ; and does the new condition 
thus established stimulate the second 
step, and so forth, or can the bee, within 
certain limits, really think, design, and 
contrive ? 
No questions are more difficult of solu- 
tion ; but while protesting against a ten- 
dency to undervalue all life below that of 
man, we must remember we have in 
our bodies processes going on which are 
not the result of volition, as when the 
blood circulates, and its particles arrange 
themselves in the pattern required to 
form our tissues and organs, and also 
that many of our actions belong to the 
class termed by physiologists, "reflex," 
that is, the result of external impressions 
upon the nervous system, in which the 
sentient brain takes no part. Thus when 
a strong light stimulates the optic nerve, 
the portion of brain with which it is con- 
nected in its turn stimulates the iris to 
contract the pupil ; and it is supposed 
that after a man has begun to walk, 
through the exercise of his will, he may 
continue to walk, by a reflex action ; as 
his feet press the ground they transmit 
an impression to the spinal cord, and the 
legs receive a fresh impulse to locomo- 
tion, although the mind is completely oc- 
