PURIFICATION. 



25 



GENERAL DIRECTIONS. 



The Aquarium is then established. The water, 

 which at first is somewhat turbid, becomes in the 

 course of a day or two clear and crystalline ; the 

 plants expand their feathery tufts in beauty, and 

 the animals begin to take possession of their holes 

 and corners, and to find themselves at home. But 

 you must lay your account with the loss of some 

 specimens ; some will certainly die in the course of 

 the first twenty-four hours, others in the first week. 

 But those which survive the first ten days may be 

 considered as pretty well established. 



It is during this period that the grand trial of 

 the experiment usually occurs. There is generally 

 a large amount of animal matter attached to the 

 sea-weeds, shells, and stones, which are received 

 from the sea, su.ch as minute Annelida, MoUusca, 

 and Zoophytes : very many of these creatures are 

 already dead, or die immediately ; but being too 

 minute to be detected and removed in detail, they 

 decay, and presently contaminate the water. The 

 first symptom of this is a slight dimming of the 

 crystal translucency, which if unchecked soon in- 

 creases to a milky whiteness, accompanied by a 

 fetid odour, and terminates in the death of the 

 whole animal collection. 



Purification. — As soon as this begins to be 

 perceived, the whole water should be drawn off by 

 means of a siphon, without disturbing the sedi- 

 ment, into pans, into which, for the present, the 

 plants and animals may be put. The Tank should 

 be wiped out and rinsed, and then the water should 



