1870.] KITCIIIE — ON AQUARIA STUDIES. 171 



Besides these little creatures Ave have mentioned there are 

 many more about Avhich nmch might be said. 



We have monads, vibrios in great numbers, always present in 

 the water of our aquarium : not only there, we may state, but in 

 the Montreal water this spring we detected, in two instances 

 living vibrios in the water immediately taken from the pipe. 



In concluding this sketch of the inhabitants of our aquarium 

 the following remarks may not be out of place. 



How little is known, by the great mass of mankind, of the 

 various creations possessed with the wonderful and unknown princi- 

 ple, " life," respecting which much more might, perhaps, be known 

 by means of patient microscopic research. By its aid we may 

 learn how admirably each little organ plays its part, and how the 

 various members contribute to each of these creatures happiness 

 in their struggle for life, for, for some wise purpose, every animated 

 being, from the monad to the whale, is battling for existence. 



There is not, perhaps, a single species of animated being whose 

 existence depends not, more or less, upon the death or destruction 

 of others. 



In the plan of nature death and dissolution seem to be indis- 

 pensable for the support and continuance of animal life. 



Man may be said, with a few exceptions, to have universal 

 empire over the other animals. Carnivorous animals and birds 

 are also engaged in this general work of destruction. 



In fishes, also, as their habits demonstrate, from the least to 

 the greatest, their appetite is almost insatiable, and their object 

 in Kfe seems to be either to devour other fishes or to avoid their 

 own destruction. 



Insects, also, are no exception to the rule. We find the same 

 struggle going on among them, each preying on, or being preyed 

 on by other species. 



Even in our aquarium this struggle can be witnessed, as illus- 

 trated in the first part of these sketches; also among micro- 

 scopic creatures, the subject of the present paper. They also 

 have their enemies, the fish swallow them in countless thousands 

 while the smaller ones supply the larger with food. 



In the economy of nature no creature lives for its own happi- 

 ness alone, but, by its destruction, contiibutes to the happiness of 

 others. The balance of power is not entrusted to any particular 

 class or species, and lie who in wisdom made them all governs 

 and guides the whole. 



