Page:Popular Science Monthly Volume 78.djvu/599

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589
EXPERIMENTAL BIOLOGY

Meal-worms constitute the most useful general food. These larvæ are placed in small, oval, porcelain sugar-bowls which because of their concave sides, prevent escape. For different animals it is necessary to provide scraped meat, fresh ant pupae, earthworms, snails, flies, kitchen scraps, chopped fruit and vegetables, as well as any small animals available. Careful attention is given to cleaning the cages. The water basins are emptied by siphons and then sponged. The plants in pots and tufts of moss and turf are changed, stones and wood scoured with hot water and the upper layer of sand or earth renewed. Smaller vivaria are employed for special experiments. In these a double cover

PSM V78 D599 Interior of the hothouse.png
Fig. 6. Interior of the Glass House for Low Temperatures.

of gauze provides an air space to ensure the circulation of air. The nests of social insects, like bumble bees and burrowing wasps, are transferred from their natural locations in the late evening when all of the family are at home. The insectaria are then placed in moss-covered ditches, or else buried in the earth, and in a few days the insects become quite contented.

In order to mitigate the conditions of confinement which unfavorably affect certain animals there are four large and many small outdoor terraria (Fig. 3).

There is a separate house (Fig. 4), bowed around the north side of the grounds, for heredity researches upon the higher vertebrates. Each of the sixteen cages has an outwardly-sloping cement floor, wire screen ventilators, heating pipes and electric lights, and opens into a garden