Page:Encyclopædia Britannica, Ninth Edition, v. 7.djvu/114

 wax-mounted set is shut up like a fossil in the heart of its stony covering. On the two halves of the flask being separated, the set of course remains firmly secured in the lower portion. Boiling water is now poured over it, and the wax thus melted out, leaving the porcelain teeth undisturbed and in situ. A cavity is thus left when the two sides of the flask are again closed, representing exactly the form of the wax removed. Raw vulcanite, or whatever other material of the kind is to be used, is now introduced with care into the space thus left by the removal of the wax. The two sides of the flask are next brought together and maintained there by the pressure of a clamp and screw. The whole is then placed in a vessel termed a vulcanizer, where it is subjected, for the space of from an hour and a quarter to two hours or more, to the action of steam at a temperature ranging up to 320° Fahr., at the end of which time the piece will be found hard and ready for finishing and polishing as may be desirable. In firing and manipulating the celluloid base some modification of this process is required, but as yet the substance is comparatively little used, and would scarcely justify further remark in this place.

What is termed a pivot tooth, again, is an artificial tooth having a metal or sometimes a wooden pin firmly attached to it; and this being inserted into the opened pulp cavity of a healthy fang, the artificial forms a secure and very perfect substitute for the original crown when destroyed by caries, broken off, or otherwise lost.

The use of artificial teeth, especially by those previously unaccustomed to them, requires considerable practice and no small amount of perseverance. The larger the artificial set,—that is, the greater the number of teeth replaced,—the greater the difficulties and the more the discomfort experienced. Time, however, works wonders here as in many other instances. It is not an uncommon thing to find a set which never has fitted well, or one which owing to many years of use does not fit well, being felt so comfortable, through mere habit of wearing it, that on a new and perfectly fitting set being made, the old one, with all its faults, is preferred to the other. A few days wear, however, of the new one generally brings all the shortcomings of the old glaringly out on its being again attempted to be worn. And in the same manner, a week or two's perseverance generally enables any ordinary set to be worn and used with comfort and facility even by patients who are for the first time under the dentist's care. Various modes of fixation are adopted for the retaining of artificial teeth in their proper situation. Atmospheric pressure, or “suction,” as it is termed, is the simplest of all, being merely the hold established between the palate and the set in the same way as occurs between a wet leather “sucker” and the stone it lifts. Another method is by what are termed “spiral springs,” a mode only applicable, however, where both an upper and lower set are worn at the same time. And a third style of fixation is where the set is supported upon certain natural teeth among those remaining in the patient's jaw. Each mode has its own advantages, and sometimes one or other method is the only one at all possible to be adopted. This, however, is seldom a difficult matter to decide by any one who has had much experience of either the operating room or the dental workshop.

The art of dentistry is difficult to acquire, and comprehends in itself processes appertaining to several separate branches of manufacture. It is, however, an art which is an extremely useful one, and has done valuable service, since it is not too much to say that in all probability many lives have been saved and a still greater number prolonged through the instrumentality of the aid afforded by the use of artificial teeth.

 DENVER, a city of the United States of America, capital of the State of Colorado, and of Arapahoe county, occupies a commanding position on the south bank of the South Platte river, where it is joined by the Cherry creek, 500 miles west of the Missouri,—its elevation above the level of the sea being 5267 feet. The town, which is of recent origin, and mostly built of brick, contains some large public buildings connected with the State administration, as well as a large public school, a State library, and churches belonging to the different denominations. It forms the centre of an important railway system, and has several factories engaged in smelting, iron founding, and wood work, besides a mint for assaying gold and silver ore, breweries, wool mills, &c. The population, which numbered 4759 in 1870, and was estimated at 15,000 in 1873, is rapidly increasing.   DEODAND (Deo dandum), in English law, was a personal chattel (any animal or thing) which, on account of its having caused the death of a human being, was forfeited to the king for pious uses. Blackstone, while tracing in the custom an expiatory design, alludes to analogous Jewish and Greek laws, which required that that what occasions a man's death should be destroyed. In such usages the notion of the punishment of an animal or thing, or of its being morally affected from having caused the death of a man, seems to be implied. The forfeiture of the offending instrument in no way depends on the guilt of the owner. The imputation of guilt to inanimate objects or to the lower animals, repugnant as it is to our habits of thought, is not inconsistent with what we know of the ideas of uncivilized races. In English law, deodands came to be regarded as mere forfeitures to the king, and the rules on which they depended were not easily explained by any key in the possession of the old commentators. The law distinguished, for instance, between a thing in motion and a thing standing still. If a horse or other animal in motion killed a person, whether infant or adult, or if a cart run over him, it was forfeited as a deodand. On the other hand, if death were caused by falling from a cart or a horse at rest, the law made the chattel a deodand if the person killed were an adult, but not if he were a person below the years of discretion. Blackstone accounts for the greater severity against things in motion by saying that in such cases the owner is more usually at fault, an explanation which is doubtful in point of fact, and would certainly not account for other instances of the same tendency. Thus, where a man's death is caused by a thing not in motion, that part only which is the immediate cause is forfeited, as “if a man be climbing up the wheel of a cart, and is killed by falling from it, the wheel alone is a deodand;” whereas, if the cart were in motion, not only the wheel but all that moves along with it (as the cart and the loading) are forfeited. A similar distinction is to be found in Britton. Where a man is killed by a vessel at rest the cargo is not deodand; where the vessel is under sail, hull and cargo are both deodand. For the distinction between the death of a child and the death of an adult Blackstone accounts by suggesting that the child “was presumed incapable of