out as a separate layer if the mixture is a salt solution.

Where two substances of moderately low melting point are mixed, the m. pt. of the mixture may be low enough for it to be liquid at ordinary temperatures, e.g., salol (m. pt. 43° c.) gives with antipyrine (m. pt. 114° c) a mixture of m. pt. 30° c, which will liquefy in hot weather.

Solid mixtures may become pasty by the withdrawal of water of crystallization from one substance by another, e.g., tartaric acid with borax.

The acid gastric juice and the alkalinity and hydrolytic action of the duodenal enzymes will, for instance, hydrolize acetyl salicylic acid into sodium acelate and sodium salicylate. Antipyrine and hexamine in the presence of the gastric juice form an insoluble compound.

Mercury oxycyanide is a non-irritant and valuable as an irrigant of the bladder or urethra, unless the patients are lacking iodides, when it will cause an intense cystitis.

The skin of a patient taking pot. iodide internally was burned by the application of hydrogen peroxide-through the liberation of free iodine.

Corrosive sublimate should not be used on wounds previously treated by iodine.

Tablets of hexamine additive compounds, such as crystozol, readily disintegrate in soft or distilled water, but only with great difficulty in hard water.

The Lunacy Line

The question of responsibility in insanity is one that will continue to disturb the law courts until there is a better definition of in what criminal responsibility consists, and a better understanding of this age-old condition.

Five doctors will declare a man insane to the degree of irresponsibility, while five lawyers will declare him sane-all being honorable men.

Insanity cannot be defined. There is no broad line of demarcation. Like the museum biological casts of skulls, rising in fine gradation from the Siamese ape to the genus homo, we may pass from the brute to the highest human, from the raving lunatic to the absolutely sane man without being able to point to the dividing line.

Medical studies in the abnormal have made great advances in recent years although they are still, and may always be, unable to give a strict unlimited definition of this ancient problem of human responsibility. But at least alienists know more than lawyers, the judge, or the jury; and their evidence, being expert, should be accepted in lieu of anything better. That they should honestly differ in many instances is understandable. That their expressed opinion should be influenced by a fee is an unfortunate reflection upon the profession, which we believe rarely occurs. After all, that must be a matter of private conscience.

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THE TEETH AND HEALTH

VIRGIL LOEB.

Although we have evidence that dental work was done as far back as the time of the Pharaohs, the care of the mouth. was not known as a factor in the conservation of health until very recent years. Little restorative work was done in early historic times, although Egyptian mummies have been found with teeth filled with metals. The chief function of the dentists of this era, among whom were numbered blacksmiths, barbers, and other artisans, was to relieve pain by simply removing the offending tooth. The importance of restoring lost teeth in an effort to maintain normal conditions in the mouth was not understood. It was not until about the middle of the last century that an almost phenomenal advancement in dentistry occurred and the science assumed its modern aspect.

The many ways in which the teeth are preserved and in which they are restored either in part or completely by the use of metals, rubber, porcelain, and other materials, is a matter of every-day information. Even the fear of the removal of all the teeth has long since been dispelled because there are very few mouths for which plates cannot be constructed to restore the masticating surface and the physical appearance of the patient; they are usually worn with complete ease and give many persons more comfort than the teeth whose function they supplant.

TREATMENT OF DISEASES OF TEETH.

With the advance in the mechanical side of dentistry came the advance in the treatment of diseases of the teeth. Instead of the removal of a tooth because it was badly decayed or because it was giving pain to the patient on account of disease of the nerve, treatment was directed toward the relief of such conditions, and teeth that previously had been condemned were saved and made to give further service. Particularly remarkable advance was made in the treatment of the root canal, the part of the tooth that carries the nerve.

Since it was known that most of the infections of dental origin are those around the tip end of the roots of the teeth, the greatest amount of skill was used in the treatment of these hair-like tracts after the removal of nerves. Sometimes the nerves had died and were infected before removal was attempted, and the treatment was thus made more difficult. Even with the greatest care, dentists were unable to fill the

canals perfectly in every case because of the tortuosity of roots and because the work was done in the dark, as it were. The use of the X-ray, however, has proved of great value in assisting the treatment, since X-ray pictures may be obtained from time to time and the progress may thus better be observed.

DISEASES OF THE TEETH AND OF OTHER PARTS OF THE BODY.

The discovery of anesthetics of various types made possible many forms of treatment. Development of antisepsis and asepis also aided greatly. While formerly little attention was given to this, it is now common practice to use the greatest care in all treatment of the teeth in order not to cause infections. When infection is found, the infection is treated before removal of the tooth is resorted to.

It was not until about ten or twelve years ago that any great attention was given to the fact that infections about the teeth can cause diseases in other parts of the body. Laboratory experiments and clinical observations at this time. established the fact that poisons generated about the teeth and absorbed into the system through the blood and other channels can cause disease in remote parts of the body. Symptoms and general examination, confirmed by X-ray examination and studies with the microscope, demonstrated the close relationship between the teeth, the tonsils, the sinuses, and the rest of the body. In many cases chronic infections have been found to have their origin in infected areas in or about these

organs.

Physicians readily accepted the theory that certain abnormal conditions of the heart and joints were frequently caused by absorption from infected tonsils, but the relation of such conditions to defective teeth was not so readily admitted. Scientific investigation during the last few years, however, is convincing evidence that in searching for the cause of many diseases, the teeth and surrounding tissues must be studied as carefully as any other part of the body. In many cases studied, the teeth are the only infected organs discoverable. Many patients suffering from rheumatism, diseased joints, nervous affections, eye affections, and even heart trouble, in whom infected areas about the teeth are found, have been relieved and cured by the treatment of their diseased teeth. On the other hand, many patients have their teeth treated, and even removed, without the slightest relief from suffering. It does not always follow, however, that because patients fail to get results after their teeth have been removed that these teeth