The educational screen (c1922-c1956])

464 School Department The Ediuational Screen of motherhood by depositing her eggs, one to a nest, in the nests of other birds— but in response to some strange instinct, as in the case of the unconscious subject of this photographic experiment, she choose a nest of birds belonging to the same species as those by whom she was reared. The scientists are showm erecting a cage of greenery in the field to serve as a blind from which to photograph proceedings. Some remarkable shots show the httle titlarks protesting vigorously but futilely at the invasion of the cuckoo, which, taking one of the titlark's eggs in her beak, lays her own in its place and flies off to a nearby tree to devour the stolen egg. Forty-eight hours later, she is caught by the camera in the act of laying an tgg in another nest, repeating the process— if the count in the film is correct, twenty-one times in the course of the season. A good close view shows the eggs in the nest of the titlark, the t^^ of the cuckoo considerably larger than the others. It hatches in twelve days, and the foster parents care for the strange fledghng, apparently unconscious that it is not their own. Splendid views show the nest and the young being fed, the feedin?? duties being assumed equally by both parents. When only three days old, and still blind, the young cuckoo works to eject the unhatched eggs from the nest, and treats the young titlarks that have been hatched in the same manner, until finally the young usurper is in sole possession of the nest, demanding to be fed even after it has learned to fly. A most unusual view shows the cuckoo, now nearly full grown and several times the size of the titlark, still being fed by the mother bird who lights on the baby's back to drop the choice morsels in the greedy mouth. Certainly a most interesting subject for camera work, and a revelation in picture form of the life history of this strange bird. The Spider (l reel) (Educational Films)— Great were the expectations of splendid results in an educational way when it was announced that there had been developed by Louis Tolhurst, a microphotography with the aid of an intense light of great brilhancy, but practically devoid of heat, all of which would allow normal activity of the tiny subjects while being photographed. And in the two subjects here reviewed, there is evident promise of great accomplishments by the process— though these reels themselves, as they have been handled, do not make full use of their splendid opportunities. Much footage is expended at the first in vindicating the spider— justifiable perhaps with a theatrical audience, but hardly necessary to the student of nature. Splendid views are given of the e^S and the nest, and the tiny spiders clawing their way out. To demonstrate the spinning ability of the tiny subject, the photographer devised a clever spinning wheel, on which the spider, while held tightly is forced to wind a thread. In this fashion 280 feet of silk are spun in less than two minutes, from the spinnerets which are interestingly photographed in closeup. The thread of silk, highly magnified, is shown in comparison with a human hair. Excellent views give a close-up of the forelegs, under microscope, as well as the jaws and several profile portraits to show various groups of the spider's eight eyes. The manner of walking the web is seen, and the spider's usefulness is demonstrated in ridding the world of numbers of flies which are shown to be disease carriers. With such possibilities, it is a matter of no small regret that the producers have automatically eliminated themselves from the educational field with the injection of such title material as, for example, "The spider's habit of laying many eggs is earnestly recommended to the hen;" "Having no mother to guide them, they dine upon each other;" and "Her multiple eye gets a multiple eyefull." Entertaining— perhaps — but there must be business of reorganizing, if the reels are to be available for serious use. The Ant (1 reel) (Educational Films)— Another of the Secrets of Life series, made possible by Tolhurst's "cold light" microphotography. The underground passages below the ant hill are most interestingly shown, with the workers digging feverishly to remove debris. The head of the ant is magnified to bring ' view its peculiar structure, and splendid clos ups demonstrate the ant's lifting power. R. markable "team work" characterizes their ai tivity, and astonishing loads are pushed and pulled with seemingly little trouble. Ant eggs furnish a novel subject for {\w camera, and the eggs hatch to larvae which in turn develop into the pupa stage, shown