THE YOUNG SCIENTIST. 
127 
some bits of decayed vegetation, and from 
tiie Jiiass of green matter in his stomach 
it was evident tliat he was not one of that 
painfuiiy numerous class in England — the 
starving poor. 
A power of one hundred and five linear, 
obtained with a two-thirds object-glass, 
and the second eye-piece, enabled all his 
motions and general structure to be ex- 
hibited, and showed that he possessed a 
piece or pieces, are protrusile. They were 
frequently brought as far as the outer lips 
(if may so call the margins of the 
mouth), but we did not witness an actual 
protrusion, except when the lips accom- 
panied them, and formed a small round 
pouting orifice. The skin of the animal 
was tough and somewhat loose, and 
wrinkled during the contractions its pro- 
prietor made. The interior of the body 
Water-Bear, 
sort of gizzard, whose details would re- 
quire more magnification to bring out. 
Accordingly the dipping-tube was care- 
fully held "just over him, the finger re- 
moved, and luckily in went the little 
gentleman with the ascending current. 
He was cautiously transferred to a Com- 
pressorium,* an apparatus by which the 
approach of two thin plates of glass can 
be regulated by the action of a spring and 
a screw; and just enough pressure was 
employed to keep him from changing his 
place, although he was able to move his 
tiny limbs. Thus arranged, he was placed 
under a power of two hundred and forty 
linear, and illuminated by an achromatic 
condenser,t to make the fine structure of 
his gizzard as plain as possible. It was 
then seen that this curious organ contains 
several prominences or teeth, and is com- 
posed of muscular fibres, radiating in 
every direction. From the front of the 
gizzard proceed two rods, which meet in a 
point, and are supposed to represent the 
maxillae or jaws of insects, while between 
them is a tube or channel, tlirough which 
the food is passed. The mouth is suctorial, 
and the tw^o horny rods, with their central 
* The best forms of this instrument are made 
by Messrs. R. & J. Beck, the erlass plates bein^ 
held in their places by flat-headed screws, and 
not by cement. This plan was devised by the 
author, and makes it easy to rene\v the glasses 
when broken. 
t The achromatic condenser is a frame capable 
of supp >rting an object glass lower than that em- 
ployed for vision, through which the light passes 
to the object in quantities and directions deter- 
mined by stops of various shapes. The appear- 
ances mentioned can be seen without it, though 
not so well. 
exhibited an immense multitude of globu- 
lar particles of various sizes in constant 
motion, but not moving in any vessels, or 
performing a distinct circulation. 
My specimens had no visible eyes, and 
these organs are, according toPritchard's 
book, "variable and fugacious." The 
same authority remarks, " In most vital 
phenomena they very closely accord with 
the rotatoria ; thus like these they can be 
revived alter being put into hot water at 
113° to 118°, but are destroyed by immer- 
sion in boiling water. They may "be gradu- 
ally heated to 216°, 252°, and even 261°. It 
is also by their capability of resuscitation 
after being dried that "they are able to 
sustain their vitality in such localities as 
the roofs of houses, where at one time 
they are subjected to great heat and ex- 
cessive drought, and at another are im- 
mersed in water." 
When vital processes are not stopped 
by excess of temperature, as is the case 
with the higher animals, the power of re- 
sisting heat without destruction depends 
upon the condition of the albumen. Solu- 
ble albumen, or, as it should be called. 
Albuminate of Soda (for a small quantity 
of that alkali is present and chemically 
united with it), after having been thor- 
oughly dried, may be heated without loss 
of its solubility; although if the same 
temperature was applied before it was 
dry, that solubility would be destroyed, 
and it would no longer be a fit constituent 
of a living creature. As Dr. Carpenter 
observes, this fact is of much interest in 
explaining the tenacity of life in the 
Tardigrada. 
The movements of the water-bears, al- 
