[3] THE AQUA-VIVARIUM. 967 



Aside from the question of economy and the advantages gained in 

 light and temperature, the capability of change or modification at 

 trifling labor and expense, as experience may suggest, will prove a 

 source of great satisfaction. While closely approximating natural con- 

 ditions, the advantages gained over the conditions of nature are like 

 those of a cultivated garden, in which everything is clean and orderly, 

 over an uncultivated field. 



Plate I represents the simplest and least expensive form of the aqua- 

 vivaria here suggested, with section of front cut away to show the in- 

 terior. There are many ways in which the interior may be arranged, 

 affording equally satisfactory results. In fact, we may follow our in- 

 dividual fancy in this respect, so that we avoid artificiality as much 

 as possible. The following suggestions, however, may be useful to 

 some. The bottom may be made uniform and a bed of three or four 

 inches of sand placed over it in which to root the plants which may be 

 introduced ; or it may be made of varying depths with hollows at inter- 

 vals in which to put the sand and plants. Another and very satisfac- 

 tory method is to root the plants in large dishes, or in rough receptacles 

 made of Portland cement or suitable pieces of stone cemented together, 

 as they can then be moved or taken out when searching for objects 

 without disturbing the growth of the plants. 



While in the aquarium tank but few kinds of aquatic plants can be 

 grown without great care and under the most favorable conditions, 

 any water-plant whatever may, by means of these aqua- vivaria, be prop- 

 agated successfully. The writer maintains, on the test of sufficient 

 experience, that all the conditions favorable to life, animal and vege- 

 table, of the largest pond may be had in this manner at trifling cost, 

 and that undoubtedly many of the vexed questions of biology might 

 readily be solved in this way. The great obstacle in the way of biolog- 

 ical research is generally the limited amount of material obtainable, 

 while rare forms are often unattainable for long periods. 



One barrel of Portland cement and two bushels of sand, mixed, cost- 

 ing less than $5, will line a trench at least 4 by 20 feet, and from 6 to 

 18 inches in depth. The water supply may be had from hydrant, spring, 

 raceway, or any available source. All the water needed, after filling, 

 is to supply the loss by evaporation and the small amount which may 

 at first percolate through the cement. Instead of a large basin a series 

 of smaller ones of varying dimensions might prove better adapted to 

 animals of different natures which might prey upon one another. In 

 constructing homes for animals of widely divergent habits there is no 

 plan other than that here proposed, which allows of such diversity of 

 arrangement. The aquarium tank is costly, and, by reason of its too 

 great and unvarying depth, and its perpendicular sides, is really un- 

 suited for much else than ornament. It is difficult of arrangement for 

 various forms of life, and is too subject to changes of temperature. In 

 some experiments in fish culture the writer found that in a trench, such 



