Fig. 3.—Aquarium formed by means of a melon glass.
Thus did the excellent method of seeking the cause of phenomena by experiments often lead us to interesting results. We had among us many children and young people who had reached the age of ardent curiosity. We took pleasure in pointing out to them the means of studying natural science; and we were not long before feeling convinced that our lessons out in the fields had much greater success than those given between the four walls of a class-room. Insects were collected, and preserved by being carefully placed in a small bottle, into which was let fall a drop of sulphuret of carbon;[2] the insect was immediately asphyxiated, and we thus avoided the cruelty of passing a pin through a living body. Having chased butterflies and insects, we next desired to study the aquatic creatures which swarmed in the pools of the neighbourhood. For this purpose I constructed a fishing-net fitted to an iron ring, and firmly secured to a wooden handle. When this was plunged under the water and drawn quickly out again, it came back full of slime. In the midst of this muddy substance one generally succeeded in finding the hydrophilus, tadpoles, coleoptera, many curious kinds of caddis-worms, tritons, and sometimes frogs, completely astounded by the rapidity of their capture. All these creatures were transported in a bottle to the house, and I then constructed, at small expense, a glass aquarium, by means of the bell of a melon-glass turned upside down, thus forming a transparent receptacle of considerable size. Four wooden stakes were then fixed in the ground, and a plank with a circular hole nailed on the top, in which the glass bell was placed. I next scattered some large pebbles and shells at the bottom of the vase to form a stony bed, poured in some water, placed a few reeds and water plants among the pebbles, and then threw a handful of water lentils on the surface; thus a comfortable home was contrived for all the captured animals.[3] The aquarium, when placed under the shade of a fine tree in a rustic spot abounding with field flowers, became a favourite rendezvous, and we often took pleasure in watching the antics of the little inmates (fig. 3). Sometimes we beheld very sanguinary scenes; the voracious hydrophilus would seize a poor defenceless tadpole, and rend him in pieces for a meal without any compunction. The more robust tritons defended themselves better, but sometimes they also succumbed in the struggle.
Fig. 4.—Cage for preserving living insects.
Fig. 5.—Small aquarium, with frogs’ ladder.
The success of the aquarium was so complete that one of us resolved to continue this museum in miniature, and one day provided himself with an insects palace, which nearly made us forget the tadpoles and tritons. It was a charming little cage, having the form of a house, covered with a roof; wires placed at equal distances forming the sides. In it was a large cricket beside a leaf of lettuce, which served as his food (fig. 4). The little creature moved up and down his prison, which was suspended from the branch of a tree, and when one approached him very closely gave vent to his lively chirps.
Fig. 6.—Frog lying in wait for a fly.
The menagerie was soon further augmented by a hitherto unthought-of object; namely, a frogs’ ladder. It was made with much skill. A large bottle served for the base of the structure. The ladder which was fixed in it was composed of the twigs of very small branches, recently cut from a tree, and undivested of their bark, which gave to the little edifice a more picturesque and rustic appearance. The pieces of wood, cleverly fixed into two posts, conducted the green frogs (tree-frogs) on to a platform, whence they ascended the steps of a genuine ladder. There they could disport themselves at pleasure, or climb up further to a branch of birch-tree placed upright in the centre of the bottle (fig. 5). A net with fine meshes prevented the little animals from escaping. We gave the tree-frogs flies for their food, and sometimes they caught them with remarkable dexterity. I have often seen a frog when at liberty watching a fly, on which it pounces as a cat does on a bird (fig. 6). The observations that we made on the animals of our menagerie led us to undertake others of a very different nature; I recollect particularly a case of catalepsy produced in a cock. I will describe this remarkable experiment, certainly one of the most curious we ever performed.