PHYSICAL EDUCATION. 61 



as oatmeal or burned arrow-root can do any harm, but, for sanitary- 

 purposes, such precautions must be supplemented by dental exercise. 

 Let a child invigorate its teeth by chewing a hard crust, or, better yet, 

 a handful of " St. John's bread " or carob-beans, the edible pod of the 

 Mimosa siliqua. Children and whole tribes of the northern races 

 seem to feel an instinctive desire to exercise their teeth upon some 

 solid substance, as pet squirrels will gnaw the furniture if you give 

 them nut-kernels instead of nuts. Thus Kohl tells us that the natives 

 of southern Russia are addicted to the practice of chewing a vegetable 

 product which he at first supposed to be pumpkin or melon seeds, 

 but found to be the much harder seed of the Turkish sunflower 

 (Helianthus perennis). Their national diet consists of milk, kukuruz 

 (hominy, with butter, etc.), and boiled mutton, and they seem to feel 

 that their Turkoman jaws need something more substantial. The 

 schoolboy habit of gnawing pen-holders, finger-nails, etc., may have a 

 similar significance. The Mimosa siliqua would yield abundantly in 

 our Southern States, and its sweet pods would make an excellent sub- 

 stitute for chewing-gum. Our practice of sipping ice-cold and steam- 

 ing-hot drinks, turn about, has also a very injurious effect upon the 

 brittle substance that forms the enamel of our teeth ; no porcelain- 

 glaze would stand such abuse for any length of time, and experience 

 has taught hunters and dog-fanciers that it destroys even the bone- 

 crushing fangs of the animal from which our canine teeth derive their 

 name. 



Various diseases of the eye, including myopia, strumous and 

 catarrhal ophthalmia, are due to a scrofulous diathesis, and sometimes 

 to a general debility, and can be radically cured only by out-door exer- 

 cise and a more nutritious diet. But a transient " weak-sightedness " 

 (Schwach-sichtigkeit, as the Germans call it), is eminently a disease of 

 the school-room, caused by a persistent abuse of the eyes, poring for 

 hours together over a spelling-book or writing by the light of a flick- 

 ering candle (much worse than twilight), as well as by the wretched 

 print of our modern dictionaries and cheap cyclopaedias. It should be 

 kept in mind that reading and writing, even under the most favorable 

 circumstances, require an effort to which the eye can only very gradu- 

 ally accustom itself. Hereditary influences and the preliminary exer- 

 cises of the infant's eye, as, in examining picture-books, the first graphic 

 essays with a slate-plencil, etc., may help to smooth the difficulty ; for 

 it is a fact, attested by the experience of all school-teaching mission- 

 aries, that the eyes of an adult, sharp-sighted savage begin to smart 

 and water at the first attempt to decipher the hieroglyphics of his 

 primer. The rudiments ought to be taught in half -hour lessons, with 

 liberal intervals of rest and out-door play ; and scrofulous children 

 should never be sent to a public school till after a novitiate of at least 

 six months of home studies. Instruct them never to pore over a book, 

 but to keep the head erect, and, at the first symptoms of dim-sighted- 



