they make an error in determining the proper curve. But when the superintendent comes he notices the mistake, pulls down the faulty piece of masonry, and corrects the error.
When M. Berthelot first saw this ant-city it had already been in existence for some years, and was in the high tide of prosperity. Ten years later it sent out a colony, which settled at the foot of a young oak, distant a few metres from the mother-city. This colony, at first weak and occupying but little ground, increased year by year. The war of 1870 for a while interrupted the course of M. Berthelot's researches, but on the return of peace there was a new surprise. The mother-city was now in a state of decline, but the colony was thriving wonderfully. In the old home there were but few births and few fruitful unions; the number of inhabitants had grown less, and the survivors were careless of their dwellings. The colony has now become the principal city, it has sent out a sub-colony which is in a flourishing condition. The old city is compared by M. Berthelot to Babylon, with its thriving neighbor cities of Seleucia and Ctesiphon.
Persian Hair-Dye.—The practice of dyeing the hair is very much in use among the Persians, who mostly employ the plant henna for this purpose. According to Dr. Tholozan, the private physician of the shah, the powdered leaves of the plant are made into a paste with hot water and then applied to the head, the hair, and the nails. This is done in a vapor-bath. This first application lasts an hour and a half to two hours, and then the parts are freely washed in water. The henna gives an orange-red color, very beautiful on a white beard, so that many old men use it. To change the reddish color of hair into a fine, lustrous black, the parts are coated, at the same sitting, with a paste formed of another powder—that from the leaves of a kind of indigo tree cultivated in Persia. This is called reng; it remains applied about two hours. The henna gives different colors according as it acts on white, fair, or dark hair. It alters very quickly in moisture, and loses its properties in long sea-voyages. Experience seems to have proved that it gives suppleness to hair, but it causes it to whiten prematurely. Fair-haired people in Persia always color their hair black, but the black is not so intense as that produced in persons of dark complexion. Skin reddened and blackened with the two pastes soon regains its natural color on being washed with soap and rubbed with the fingers, whereas the dye adheres firmly to the hair, which it penetrates. Reng is sometimes used alone, and gives a blue-violet color.
About Oleomargarine.—Mr. John Michels points out, in the American Journal of Microscopy, the differences between butter and oleomargarine as observed with the microscope. Two woodcuts illustrate the paper, the one exhibiting the microscopic appearance of oleomargarine, the other that of butter. In the former substance are seen numerous stellate or feathery crystals, together with globules. In butter none of the crystals are seen, the whole field of the microscope being filled by the globules, with perhaps crystals of common salt. Besides these stellate crystals, Mr. Michels found in all the specimens of oleomargarine examined by him fragments of tissue and muscle, also certain cells of a very suspicious character. What these cells may be the author does not assume to decide, but he appears to suppose that they might possibly be the larval forms or eggs of entozoa. Some of Mr. Michels's observations on oleomargarine and its suitableness for human food having been called in question, in particular his statement that living septic organisms may exist in the artificial butter, he submitted the matter to the Rev. W. H. Dallinger, of Liverpool, a very high authority indeed. Mr. Dallinger's reply is given in full by the author. He writes: "A temperature of 120° [which is the highest temperature employed in the manufacture of oleomargarine] is not by any means seriously, and certainly not permanently, injurious to even the adult forms of the putrefactive organisms." Again: "Quite as serious a matter is that of the introduction, through oleomargarine, into the human intestinal tract of eggs of entozoa. I have made enough experiments to say that the eggs, for example, of the nematoda are practically uninjured by 120° Fahr. This," Mr. Dal-
