Page:The Book of the Aquarium and Water Cabinet.djvu/157

Rh unless confined by a glass lid or gauze. But he is now a true frog, delicately mottled, agile in his movements, very clever in jumping and swimming—his tadpole tail entirely absorbed, and his whole system metamorphosed. If he interested us before, he is still more interesting now, for in the structure and economy of his frame Nature reveals phenomena typical of animal life in all its orders and gradations. Hence the frog is the victim of the philosopher; he suffers spasm under the galvanic wire, blindness under the glare of the microscope lamp, tetanus through being dosed with strychnine, and innumerable other agonies in which operators detect analogies that throw a light on the fundamentals of animal life, and that even aid in the explanation of the subtle organism of man himself.

.—The instructions already given for the management of Aquaria will be found to embrace most of the points involved in the management of beetle and larva jars, for these are but Aquaria on a smaller scale. The chief matter is to separate the species as much as possible, so that the carnivorous kinds shall not destroy the harmless ones; and on this plan the study of each kind is greatly facilitated. Since the jars afford the best means for the culture of choice aquatic specimens of the various kinds of Riccia, Conferva, Nitella, Lemna, and other minute water-weeds may be used for maintaining the necessary balance in