THE YOUNG SCIENTIST. 
than would at first be supposed. When 
well exhibited the tentacles have a lustre 
between glass and pearl ; the body, in a 
favorable specimen, is like a crystal cup, 
and the food, usually composed of small 
red and green globes, glows like emeralds 
and rubies, as if in the height of luxury 
the little epicure had more than rivalled 
Cleopatra's draught, and instead of dis- 
solving, swallowed its jewelry whole. So 
lustrous and varied in color is the whole 
appearance of the animal under these 
circumstances, that it is frequently 
alluded to by one of our first artists, to 
whom it was displayed. 
It is said by some authors that the 
tentacles are used to seize prey. This 
never occurred under my observation, 
although their basal portions are often 
approximated when an object is forced 
down to the grinding apparatus below. 
The Stephanoceros is a ravenous feeder, 
and swallows a variety of creatures. 
Green vegetable monads, rich red and 
brown globes of similar characters, and 
any animalcule that comes in her way is 
acceptable; and even good-sized rotifers 
do not escape her all-consuming maw. 
On one occasion I noticed one of the 
loricated sort, more than half as long as 
one of her tentacles, rapidly swallowed, 
and passed downwards without attempt- 
ing to escape, Objects much too big for 
the gizzard are often gulped down, and 
probably receive a preliminary softening 
and maceration in the crop. Very often, 
when food is plentiful, the creature is 
filled to the brim, but still endeavors to 
continue her abundant meal. From the 
presence of large quantities of food and 
the density of the integuments, the 
gizzard cannot always be seen ; but in 
favorable specimens its teeth may be ob- 
jserved busily at work. 
At the base of the tentacles small masses 
of matter may be discovered, which are 
probably nervous ganglia and other 
organs ; and Ehrenberg discovered small 
vibrating bodies, supposed to be con- 
nected with the function of respiration. A 
single egg, is often foun i, and the ovarium 
is said to develop but few at a time. 
Two red eyes are found in young speci- 
mens, but in adults they either disappear 
or are not conspicuous. The Steptiano- 
ceri are sociable animals, and when one 
is found, others are probably near at 
hand. Several may often be discovered 
on the same brarlch of a small water- 
plant, of various dimensions, and in 
different stages of growth. The full size 
is about 1-36" in height, and from its 
magnitude care is required not to crush 
it in the live-box. When specimens are 
plentiful, some should be placed in that 
convenient receptacle ; and others with the i 
plant on which they are growing, in a 
glass cell or trough, where they have 
I more room to display their motions, and 
can with fresh supplies of w^ater, be pre- 
served for days and weeks. With oc- | 
casional renewals from one pond, I was \ 
able to keep up a stock for about three ! 
months, and never had objects which gave i 
more pleasure to myself or to my friends. 
Cleaning Engravings. ' 
IT very often occurs that professional j 
photographers have brought to them ; 
engravings to copy, and it generally hap- | 
pens that they are old, discolored, and 
stained in great patches about the color ! 
of gingerbread. Of all colors this is, pho- j 
tographically, most objectionable, and it 
is nearly impossible to obtain a passable 
result. If the engraving happen to be a 
valuable one the photographer, as a rule, ; 
is almost afraid to try and clean it, lest 
he should spoil it, especially with the re- 
ceipts we find published in various receipt 
books. Only a short time ago I was look- 
ing over some of these books. One advo- 
cated chloride of lime, another hydro- 
chloric acid, and agents of a similar 
nature. We all know the bleaching power 
of such powerful agents. With regard to 
the first named, I for one, always shun it, 
as when once it gets in to any organic 
material it is very difficult to eliminate it 
again, and it is well known that if any of 
the lime compounds are allowed to re- 
main the whole fabric, in the course of 
time, rots and drops to pieces. 
I know many amateurs who like this 
kind of practice in copying old engrav- 
ings, and are not aware that there is a 
means of cleaning and restoring them 
without the slightest possible risk; and, 
moreover, the plan I am about to pro- 
pose is a very inexpensive one indeed. 
Staining not only occurs in old engra- 
vings, but in modern ones we very often 
see parts of a picture stained sometimes 
through a knot in the back board, or the 
wood of the same being full of turpentine. 
All these markings can be removed. My 
plan is to get a dish or china tray a little 
larger than the engraving to be operated 
upon ; if smaller there is a great risk of 
tearing and damaging the engraving. 
The bleaching agent is no other than 
Holmes' ozone bleach. The strength I 
prefer to any other is one part of ozone 
bleach to ten of water, well shaken up 
before pouring into the dish. A much 
stronger solution can be used— in fact, I 
have used it as strong as one to five of 
water; butjthe reason I use the weaker 
one is that l am of the opinion that the 
less of the agent we use the less we have 
to soak out of the paper afterward. I im- 
merse the engraving in the solution, face 
upward, avoiding bubbles. The only cau- 
tion to be observed is that when the en- 
graving is sodden with water it is some- 
