I40 AQUATIC MICROSCOPY FOR BEGINNERS. 



manded by their successors. But why it is that one 

 class will die out to be followed by another cannot be 

 positively known. The fact however remains, and the 

 microscopist in order not to lose some rare or interest- 

 ing creature, should not only examine the gathering 

 as soon as possible after making it, but at frequent in- 

 tervals as it stands on his table in the miniature aqua- 

 rium near his window. 



A north window is the best place for the aquarium, 

 because the light from that part of the sky is more 

 diffused and more even in quality. Direct sunlight 

 will surely kill the Infusoria as well as much larger 

 and presumably more hardy aquatic creatures. After 

 a microscopical collecting trip, never place the bottles 

 in the sun for any length of time, and never allow di- 

 rect sunlight to shine upon the microscopical aquarium. 



But even the microscopical aquarium must be prop- 

 erly made if microscopic life is to- be the object of re- 

 search. A vessel of clear water will not amount to 

 much. If Infusoria, or Algae, 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 transferring 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 water-soaked twigs, and peb- 

 bles, and fronds of 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 Infuso- 

 ria, which often lead a roaming life while young, only 



