294 Tue Microscope. 
But even, the microscopical aquarium must be properly made 
if microscopic life is to be the object of research. A vessel of 
clear water will not amount to much. If Infusoria, or Alge, or 
Rotifers, or worms, or any other kinds of life are to develop in 
these jars, their spores or eggs must first be there, food must be 
readily accessible to the voracious creatures, and their native 
habitat must be imitated as nearly as possible. All this can be 
done by transfering a small part of the pond or pool or ditch 
to the aquarium on the table. Do not act as I have known 
some collectors to act, and carefully reject all the water-seaked 
twigs, and pebbles, and fronds of “duck meat” (Lemna), and 
bits of aquatic plants, and pieces of decaying leaves. These 
things are often the most valuable in the collection. The little 
sticks may bear most beautiful colonies of sedentary Infusoria, 
for all animalcules are not free swimming; they often lead a 
roaming life while young only to settle down in some pleasant 
place when they have arrived at hours of discretion, remaining 
in that spot permanently, or until the microscopist dislodges 
them, or some aquatic animal swallows them, or until they ac- 
complish their life-work and die. A pebble may be a nugget 
of microscopical richness. Aquatic plants, especially those like 
Myriophyllum or Ceratophyllum, whose leaves Nature has cut into 
numerous almost thread-like divisions, are capital places to 
search for those animals which live in colonial clusters attached 
to submerged objects; and the rootlets of duck-meat, Lemna as 
it is called, are almost as sure to be well supplied with these 
colonial or communistic groups. The decaying leaves are always 
either abounding in Infusorial or other microscopical organisms, 
or they carry the germs that shall develop, or they supply by 
their disintegration an abundant food supply. Take all these 
things for the specie jar aquarium, using judgment as to the size 
and quantity. 
When the jars have been standing in the window for some 
weeks, their sides will gradually become obscured by the growth 
of an amorphous vegetable matter which will be exceedingly 
annoying to the microscopist, as it will conceal all within the 
vessel, and any promising bit of weed, or little swimming crea- 
ture may escape capture because the dipping tube cannot be 
properly directed. The difficulty is easily overcome. With a 
small sponge tied to the end of a stick gently rub the growth 
from the glass, and allow it to form a part of the food supply of 
