108 
THE YOUNG SCIENTIST. 
saw them clearly and beautifully resolved. 
These lines number about 34,000 to an 
inch. 
So much for balsam lenses. If any of 
the readers of this journal experiment in 
this direction, I should be pleased to hear 
what success they have. 
Allen Y. Mooee. 
Tulare, Cal, June 17, 1878. 
Paste Eels. 
1 N reply to a correspondent who asks how 
paste eels may be raised, one of our 
scientific cotemporaries says that paste, if 
left to turn sour, will soon swarm with these 
curious little creatures. The directions 
usually given are to boil flour and water, as 
in making ordinary paste, and set it aside 
until it becomes sour, stirring it occasionally 
so as to prevent the growth of mould. We 
have tried this plan over and over again, 
and have never succeeded once. We have 
kept the paste until it had passed through 
all stages of decay, but never, under ordi- 
nary circumstances, have eels made their 
appearance. And, indeed, it would evi- 
dently have been impossible to find them, 
unless they had either been developed by 
spontaneous generation, or the eggs or 
germs had been carried through the air. 
That they could be developed by spontane- 
ous generation, few will believe, and that 
their eggs or germs are ever carried by the 
air, we have abundantly disproved by the 
following experiment: A jar of paste with- 
out eels was placed in the centre of six jars 
containing paste which seemed to be almost 
alive with them; these seven jars were 
allowed to stand for weeks, the only addi- 
tion being a little well boiled (and cooled) 
water to keep the paste from drying up. 
Under these conditions the eels in the outer 
jars throve until the paste seemed to be 
literally a mass of eels and nothing else. 
But in the central jar no eels ever made 
their appearance. 
The question arises then, How do the 
eels ever originate in paste, unless when 
placed there by design? The only solution 
that we have found to this question is that 
they come there from the water used to 
dilute the paste. It very frequently hap- 
pens that river, pond or cistern water con- 
tains small eels very similar to the paste 
eel, and it is more than probable that these 
eels, developing rapidly in the new con- 
ditions in which they are placed, cause the 
paste to swarm with their progeny. Those, 
therefore, who desire to raise a stock of 
eels, must, after making the paste, add to 
it a little water from the bottom of a pond 
or cistern. In this way a start may often 
be obtained. But to merely expose a lot of 
boiled paste to the air until it becomes sour 
will in almost all cases end in failure. The 
easiest method, however, is to obtain from 
some friend a little paste containing eels, 
and add this to some paste that is three or 
four days old. The paste should be well 
mixed, and stirred daily to prevent the 
growth of mould. 
A New Form of Stage Forceps. 
THE stage forceps is such a useful and 
convenient accessory to the micro- 
scope that any improvement whereby it is 
made more perfect or less costly is of value. 
Mr. George Wale has invented a new form 
of this little implement, which is shown in 
the accompanying cut. It will be seen that 
the forceps proper are made of a single 
wale's stage forceps. 
piece of sheet metal bent to a shape which, 
though easily understood, is peculiar and 
very difficult to describe. Under ordinary 
circumstances the forceps remain closed, 
and take a firm grip of any object placed 
between their prongs, but by pressing on 
the wing-like expansions of the metal strip 
forming the jaws, the latter open and the 
object falls out. These forceps can be made 
more cheaply than any others in market. 
