Page:Popular Science Monthly Volume 3.djvu/537

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ing them. To this class belongs the Anergates atratulus, a species which have no workers, but which, both males and females alike, live in company with the workers of the Tetramorium cœspitum, and are tended by these latter, though the terms on which the association is formed are not known. The Strongylognathus testaceus also lives by the charity of the Tetramorium. But the author has discovered a species of Strongylognathus having true slaves.

Then there are mixed communities, where two species which usually live separately, lead a life in common; but this is a thing of very rare occurrence, and but little investigated. M. Forel has found ants' nests inhabited by the Formica truacicola and the F. fusca, by the Tapinoma erraticum, and the Bothryomyrmex, etc. On the other hand, he has also met with communities of the F. sanguinea, without slaves.

Inherited Traces of Surgical Operations.—In his fifth lecture on "Eggs," published by the Tribune of April 26th, Prof. Agassiz has the following on the transmission of individual peculiarities produced by surgical operations: "But, while the office of inheritance is to preserve typical features, its power to transmit individual peculiarities is also wonderful. My friend Dr. Brown-Séquard, who has made more experiments among animals than any man living, continuing them upon successive generations, and ascertaining what diseases may be transmitted, has stated facts to me which almost defy belief. These facts are unpublished. I will give a few of them. He has found that the disease of epilepsy can be induced in guinea-pigs by certain operations, and that this disease, being so introduced into the system, may be transmitted from generation to generation, and thus become hereditary. Where such operations have produced malformations of the skin, as is often the case, these also have been transmitted; or, where the paws have been affected by such operations, the peculiarity has been also transmitted. Malformation produced by these experiments as a disease during the life of a parent has been passed down to the offspring, and even habits arising from disease have been inherited in the same way. In one such case the peculiarity existed in the female; in another it was produced in the male. In the latter instance the male transmitted its own diseased condition to another generation through a healthy female. More than this, the female through whom these diseased descendants had been produced eventually became herself diseased in the same manner as the male. These facts have a fearful significance. With reference to the process, the subtle influence by which such results are produced, we must be silent for the present, since we cannot explain or understand it. All that we know is, that a material combination takes place which enables us to say that these individual peculiarities are sifted through the egg of the female and the spermatic particles of the male, and may reappear in their progeny."

Clay-eaters.—The Agmara Indians, inhabiting the shores of lake Titicaca, and the lofty plateau of the Andes, find the struggle for existence hard, at an altitude of more than 11,000 feet above the sea-level. Their principal articles of food are quinoa, a coarse grain resembling rice, and potatoes, of which tuber their country is the original home. The difficulty of boiling food at so great an altitude necessitates the previous maceration of all articles intended to be so cooked. The potato is, therefore, prepared for storing and use by exposing it to the frost; then it is placed in water, and stamped into a paste; all the soluble matter is washed out, and the starchy and farinaceous substance alone remains. This is called chuno, and it is made into a nutritious though insipid soup. The Agmaras use clay as an article of food, mixing it with quinoa. The clay they use is of a whitish color, and rather gritty. Careful analysis shows that it contains no organic matter, and therefore it must be used merely for the purpose of producing a satisfactory though delusive distention of the stomach.

The Faculty of Direction.—It will be remembered that, in the course of the discussion as to hereditary antipathy, a side question was introduced by Mr. Wallace, namely, the faculty possessed by certain