Page:Popular Science Monthly Volume 48.djvu/152

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142
THE POPULAR SCIENCE MONTHLY.

well established that there was much danger of the milk being contaminated if the cow from which it came had tuberculosis of the udder, attention was restricted to the question whether the milk was ever infected when the disease was confined to other parts of the animal. Bacilli were found in the milk from twelve out of thirty-six tuberculous cows. Milk from six out of fifteen infected cows produced bacilli when inoculated into guinea-pigs, and the milk of four out of nineteen cows produced bacilli in rabbits. Bacilli developed in two out of forty-eight rabbits, five out of twelve pigs, and eight out of twenty-one calves to which milk from tuberculous cows was fed. It is interesting to note that microscopic examination revealed bacilli in only one out of thirty-three samples of milk ordinarily supplied to consumers in Boston, but bacilli appeared in rabbits after inoculation with three of the samples which gave negative results under the microscope. A circular sent to eighteen hundred physicians and veterinarians asking "Have you ever seen a case of tuberculosis which it seemed possible to you to trace to a milk supply as a cause?" brought replies from one thousand and thirteen, eight of whom reported cases where they believed children had been infected by mother's milk, and eleven reported cases in which children had been infected by cow's milk, while sixteen spoke of suspicious cases which they had not been able to verify. Some results of inquiries as to the prevalence of bovine tuberculosis and as to tuberculosis among Hebrews are also given.

Extermination of British Species.—In the inaugural address of the president of the Cheltenham, England, Natural History Society, Dr. E. T. Wilson, on Man and the Extinction of Species, are some historical notes on the disappearance of certain species in the British Islands. Within limited areas, the author says, species were not unfrequently eradicated before the use of firearms, as the beaver m England, which, though once common, was in the twelfth century only to be found in one river in Wales and one in Scotland; and wolves, which were practically exterminated in four years after the demand by Edgar for a tribute of five hundred heads annually from his Welsh subjects. "But even the introduction of firearms at first did little beyond giving man an increased advantage in his contest with the more formidable of the lower animals. Far otherwise is it, however, when man, the primitive hunter, gives place to man the tiller of the soil, man the cultivator, who fells forests, drains marshes, plows prairies, and in a thousand ways alters the face of Nature." To most of the larger quadrupeds, and to many birds, space is of vital importance, and space is being rapidly curtailed. The bustard, described by Bewick as common on the plains of Wiltshire, Dorset, and Yorkshire, has disappeared before advancing cultivation. The egret and the crane, once common in Scotland, are now among the rarest of visitors. Drainage in the broads and fens has led to the banishment of many former inhabitants, such as the grey lag goose, and in many parts the bearded tit. Between 1825 and 1855 the avocet, the bustard, and the godwit ceased breeding in Norfolk. About the same time the ruff became uncommon, and the bittern left off breeding regularly in 1850. Eagles and large hawks, such as the kite and the buzzard, and among mammals the otter and even the harmless badger, are becoming rarer year by year before the gun or the trap of the gamekeeper; while the trade collector, with his demand for whole clutches of eggs, contributes to the destruction of some of the rarer species. In 1893 an item was published that two sloops had visited the island of Foula in the Shetland?, the chief breeding station of the great skua, and carried off several dozens of the eggs, and there was reason to believe that not a single young bird was reared on the island during the breeding season of that year.

The Feigning of Death.—The probability of this phenomenon being a pure reflex, in most animals, is indicated by the following experiment on a currant moth, whose powers of "shamming" are so familiar, which is described in a recent letter to Nature by a Mr. Oswald H. Latter: "The moth was first seized by one wing, and it at once feigned death; thereupon its head was cut off with a pair of scissors, and the animal continued to feign death. I use the expression advisedly, for absolute immobility was maintained for some seconds and then violent fluttering