INFUSORIA. 141 



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 

 accomplish 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 abundance of food. Take all 

 these things for the specie-jar aquarium, using judg- 

 ment as to the size and quantity. 



When the jars have been standing in the window for 

 some weeks, their sides will gradually become ob- 

 scured by the growth of an amorphous vegetable mat- 

 ter which will be exceedingly annoying to the micros- 

 copist, as it will conceal all within the vessel, and a 

 promising bit of weed, or a little swimming creature 

 may escape capture because the dipping tube cannot 

 be properly directed. The difficulty is easily over- 

 come. 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 the microscopic ani- 

 mals within the aquarium. The deposit is not entirely 

 the evil it at first appears to be. 



When the collector is gathering aquatic plants for 



