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Widal Test

typhoid, fever, wine, serum, juice, blood, patient, week and drop

WIDAL TEST, -THE.—It is sometimes very difficult to determine in a given case whether the patient is suffering from typhoid fever or from one of a large number of other diseases that frequently resemble it very closely, at least during the earlier stage of the illness. In the second week or later there is usually no great difficulty in determining whether or not the case is one of typhoid fever, but during the first week or so the symptoms may be identical with those produced by influenza, tuberculosis, meningitis, pneumonia, appendicitis, and other conditions ; thus making it difficult to arrive at the correct diagnosis. Typhoid fever may begin in so many different ways, and is so often irregular in its early manifestations, that physicians for years endeavoured to discover some certain means of recognising it, but, in spite of all their efforts until quite recently occasional mistakes were unavoidable. Now, however, thanks to the progress that has been made in bacteriology, the diagnosis of typhoid fever can be made with almost absolute certainty. While the principle underlying this test, which is called the Widal test in honour of the French physician who did most to make it a routine procedure, is not very difficult to understand, it requires a certain amount of practice and experience to carry it out in such a way as to make it a reliable source of information.

The test depends on the fact that, when animals or human beings are inoculated with the bacteria or germs of certain diseases, peculiar changes take place in the blood. For example, when typhoid-bacilli are allowed to grow in beef broth they swim about very actively, and if a drop of the fluid is examined under a powerful miscroscope the separate germs are seen to be in constant motion, but never touching each other or forming groups. If to a drop containing these bacilli there is added a drop of serum (the liquid part of the blood) from a normal person or from someone suffering from any disease except typhoid fever, no change is observed, but if the scrum is obtained from a typhoid fever patient the effect is prompt and very striking. The germs become less and less active in their motion until finally all movement ceases, and instead of being scattered about one by one they all collect in clusters or clumps, so that no single indiViduals arc anywhere to be seen. The rapidity with which this clumping takes place depends on the concentration of the serum used ; and in practice it is customary to dilute the serum with twenty or more parts of fluid and to add one drop of this mixture to the culture of bacilli. The serum is obtained by pricking the patient's finger or ear-lobe with a small lancet and collecting a few drops of blood, from which the serum can be separated in several ways. While the Widal reaction is of inestimable service to the physician, there are a few—a very few—exceptions to its reliability, and it also has the disadvantage of sometimes not appearing until the second week of the disease. Usually, however, it is present toward the latter part of the first

week. Early in the illness a single negative test is not conclusive, and in cases in which the reaction is not present when first tried it should always be repeated at intervals of a few days until either a positive result is obtained or the disease develops in such a way as to prove that some condition other than typhoid is responsible for the illness. The boards of health of nearly all cities of any size now make the \Vidal test for physicians as a regular part of their duty to the public ; and as the blood to be examined can easily be sent by mail, no patient living in a region where there is a post-office need he deprived of the benefit of this invaluable aid to diagnosis when typhoid fever is suspected. In view of the importance, not only to the patient, but also to his family and neighbours, of having typhoid fever recog nised early if it is present, resort to the \Vidal test should never be neglected in doubtful cases.

WILD GINGER.—See AsARum.

WINE.—The fermented juice of the grape. The grapes are pressed into large vats, whereupon the juice, or " must," is freed from the solid residue, and left to undergo fermentation. The juice consists mainly of water, holding in solution grape-sugar, tartaric acid, dextrin, albumen, and various other extractives ; and it ferments readily without the addition of any foreign substances. If the quantity of sugar present in the juice be insufficient, more is usually added: The process of fermentation converts the grape-juice into alcohol and carbonic acid, the latter escaping as bubbles, and giving the young wine, while still cloudy, its piquant taste. The more sugar the grapes contain, the richer in alcohol does the clarified product become. \Vines made from the sweet southern grapes are, therefore, the most intoxicating. Champagne, Port, Madeira, Sherry, Tokay, Malaga, and Marsala contain between 12 and 20 per cent. of alcohol ; Claret, Moselle, Rhine wine, and Burgundy, between S and 12 per cent.

On account of the comparatively large amount of alcohol contained in wine, even the lighter varieties must be regarded as absolutely injurious in the treatment of children. Stronger wines are actual poisons to children below the age of fourteen. In adults, wine may occasionally be indicated as a stimulant in the treatment of certain diseases. Moselle wine, for instance, has a stimulating effect on the intestines on account of the acid it contains. The contrary effect is produced by clarets, which contain a considerable amount of tannic acid, rendering them astringent. Champagne owes its effervescent qualities to its contents of carbon dioxide gas. Sherry wine is used as a menstruum in various pharmaceutical preparations.

WINTERGREEN.—See GAULTHERIA.