THE YOUNG SCIENTIST. 
117 
out, is chiefly produced by the contraction 
of the endocyst ; vvliile the inversion, or 
getting in again, is performed by the long- 
muscles, which, when the animal is ex- 
tended, are seen attached to it like ropes. 
Upon these muscles Professor Allman re- 
marks that they are "esi)ecially interest- 
ing in a physiological point of view, as 
they seem to present us with an example 
of true muscular tissue, reduced to its sim- 
plest and essential form. A muscle may 
here be viewed as a beautiful dissection 
far surpassing the most reflned prepar- 
ation of the dissecting needle, for it is 
composed of a bundle of elementary 
fibres, totally separate from one another 
through their entire course." He further 
adds, "The fibres of the great retractor 
muscle are distinctly marked by trans- 
verse striae — a condition, however, which 
is not at all times equally perceptible, and 
some of our best observers have denied to 
the Polyzoon the existence of striated 
fibre." 
We can confirm the fact of this sort of 
fibre being i3resent, but we fancy a reader 
not versed in the mysteries of physiology 
exclaiming, ' What does it matter whether 
his fibres are striped or not ? ' 
Physiologists used to suppose tljere was 
a strong and marked distinction and 
separation between striped muscles, that 
is, muscles the fibres of which exhibit 
transverse stripes when magnified, and 
those which do not. Kolliker, however, 
says this decided separation can no longer 
be maintained,* and he gives instances in 
proof of the connections that can be traced 
between the two forms. In the higher 
animals the striped muscles are the 
special instruments of ivill, and of move- 
ments that follow, or are accompanied 
by, distinct sensations. Striped fibre must 
be regarded as the highest form ; and as 
a muscle of this sort contracts in length 
it increases uniformly in breadth. 
There are many other genera and species 
of fresh-water polyzoa besides the Pliuna- 
tella repens, and they are found attached 
to sticks, stones, or leaves, generally to 
the under surface of the latter. They are 
all objects of great interest and beauty, 
which, whatever their diversity, con for in 
sufficiently to one type that the student 
who has observed one, will easily recog- 
nize the zoological position of another. 
They should be viewed by transmitted and 
br dark-ground illumination, which pro- 
duces very beautiful effects. To observe 
them in the performance of their functions, 
they require more room than the live-box 
can afford, but are well shown in the glass 
trough, whose movable diaphragm en- 
ables them to be brought near enough to 
the object-glass, for the use of a/ power of 
about sixty linear for general purposes, 
and of from one to two hundred for the 
examination of particular parts. Por a 
more detailed examination dissection 
must be emi,)loyed, but all that we have 
mentioned can be seen without injury to 
the living animal, if specimens are kept 
till new cells are formed in water, which 
does not contain enough dirt to render 
their integuments opaque. 
63. 
' Manual of Human Microscopic Anatomy, p 
Scientific Absurdities. 
WHEN scientific writers depend upon 
their imagination for their facts, 
they are apt to make rather wild work. 
There are very few men who can follow 
closely, step by step, the scientific neces- 
sities of any supposed combination, and 
hence when a supposed scientific discovery 
is described witJiout having been actually 
put to the test, the writer is very apt to 
overlook some essential point. A writer 
in Les Mondes, under the heading, 
"Hunting by Electricity," thus describes 
an experiment, which, as any tyro ought 
to know, will not work : " A new applica- 
tion of the Euhmkorff coil has been made 
in the neighborhood of Marseilles. Instead 
of using bird-lime on trees which are fre- 
quented by birds of passage, a copper wire 
is wound around the trunk and a decoy 
attached to a neighboring staff. When a 
numerous flock has been attracted by the 
decoy, a shock is sent by the commutator, 
and they are more surely stunned than by 
a rifle." 
That the bird may be killed, or even 
stunned, it is necessary that the shock be 
passed through it, and to do this it must 
be placed between the poles. A good con- 
ductor connecting these poles, may be 
safely held in the hand, no matter how 
powerful the discharge may be. We 
should be very much surprised to learn 
that the birds in the neighboring wood of 
Marseilles are in the habit of deliberately 
sitting down between the poles of a 
Euhmkorff coil,, so as to be killed, even 
though there is a handsome decoy at- 
tached to a neighboring staff. 
The same writer also tells us that " ex- 
periments of a similar kind have also been 
made by M. Dalmas upon the vines at his 
country-seat, and powerful shocks are 
said to have destroyed the parasites to- 
