��POPULAR SCIENCE MONTHLY.
��dren : (1) In cases of ill health from tuber- culosis, etc., anccmia being almost always a prominent symptom ; and (2) in healthy children, the habit being formed in infancy and disappearing spontaneously when the children are about three years old. Dr. Thomson regards the habit in this latter class as analogous to thumb-sucking, perpet- ual rocking to and fro, or constant rolling in bed, in which some children find delight and which they lose when they pass out of in- fancy. The materials selected are chiefly wall plaster and cinders. One child varies the latter by pushing the hearth brush into the ashes and then licking the dust oif as a great delicacy. The habit, as is well known, is common among imbeciles and idiots ; but Dr. Thomson's cases were free from mental disorder. Dirt-eating may lead to serious consequences when the material eaten con- tains harmful matter. The native Egyp- tians, who, observing the marvelous fertiliz- ing power of Nile mud, imagine it must be equally nutritious for men, habitually eat it, with the result of infecting themselves with the ova of anchylostoma, bilharzia, and other parasites.
Piano Toneli. When a certain point of perfection has been attained in piano- play- ing it becomes very hard to distinguish in- equality of touch ; yet, owing to the varying strength of the fingers, it is only with much practice that perfect equality is possible. An account of an apparatus for graphically registering these inequalities is given in a recent issue of Nature. The instrument was devised and used for experimental work by MM. Binet and Courtier. It is said to be simple in construction and vei'y accurate. The advantages claimed for the instrument are threefold : (1) It is found that the vol- untary movements of the pianist can be ob- served without putting him to any restraint or embarrassment, for the resistance of the keys is not affected nor is the exterior of the piano altered ; (2) for teaching purposes the device has been found of great use ; the rec- ord made on a roll of paper shows the faults so precisely that, although they arc scarcely perceptible to the ear, there is no denying their existence ; (3) written music can not show every slight change in time the com- poser might desire, but by applying the
��graphical method this diflSculty is elimi- nated and the time will be reproduced with the smallest details.
The Cigar-Case Bearer. A new fruit- tree pest has recently appeared in New York State, and is described in a bulletin from the Cornell Experiment Station. It is called the cigar-case bearer. Owing to its small size and peculiar habits, the insect in any stage will be rarely noticed by a fruit-grower, and yet the second one of the curious suits or cases which the little caterpillar wears is conspicuous enough to reveal its presence to the casual observer. The first suit is manu- factured in the fall, to be worn all winter; but about the 15th of May the half-grown caterpillar finds this too small, and proceeds to make a summer suit which resembles a miniature cigar in shape and color. The first indication of the insect's presence oc- curs on the swelling buds of apple, pear, or plum trees. The work on the expanded foliage is seen in skeletonized dead areas, which have near their centers a clean-cut round hole through one skin, usually on the under side of the leaf. The caterpillars also often attack the growing fruit. It is only possible to fight the insect successfully in the caterpillar stage, and even then it re- quires very thorough work to destroy it.
A Contemplated Antarctic Expedition.
A committee has been formed in London to promote a mercantile and scientific antarc- tic expedition, and has already published its plan of operations. The scientific contin- gent, which will be accompanied by Mr. C. E. Borgrevink, will consist of twelve English- men trained in science, equipped with the necessary huts, dogs, sledges, etc., and will be left at Cape Adare, with the expectation of spending one year in South Victoria Land. The investigations will include the work of a land party toward the south magnetic pole, there to make magnetic observations ; a sur- vey of the coast line of the open bay, with exploration and soundings of fiords and bays ; the making of zoological, botanical, miner- alogical, and geological collections; dredg- ing ; and barometrical, thermometrical, mete- orological, pendulum, air-current, and water- current observations. While the scientific men are thus exploring the land, the vessels