Page:Popular Science Monthly Volume 23.djvu/61

Rh do not know that the artificial method can at present compete with the natural, but it will probably do so before long, if it does not now. Little did the discoverer dream of the result when he undertook his investigation. When glycerin and oxalic acid are mixed, and the mixture distilled, the chief product under ordinary circumstances is formic acid, a substance found in nature in the bodies of certain ants. Formic acid had been made by the method mentioned for a number of years before it was noticed that something else is formed at the same time. This observation was made about the year 1870, by Tollens, in a chemical factory. On looking into the matter more closely, it was found that the second substance is allyl alcohol, already well known. Now this allyl alcohol is closely related to the oil of mustard, but, up to the year 1870, no method was known by which it could be prepared easily and in large quantity. Now it can be made, thanks to the investigation of Tollens, in any desired quantity. Its transformation into the oil of mustard is a comparatively simple matter, and thus starting from the two common substances, glycerin and oxalic acid, it is now practical to pass to the valuable oil of mustard. You will observe that, in this case, the object of the discoverer of the method was not to get the oil of mustard, but simply to learn what else could be formed besides formic acid under the conditions above mentioned. The question which he proposed to answer was not a very elevated one, nor one the answering of which was at all likely to lead to results of practical value; but, nevertheless, a valuable result did follow.

At the present time there are several chemists engaged on investigations which promise eventually to be of the highest value to pharmacy. Let me attempt to give you some idea of these. For a long time it has been known that from many plants there can be extracted certain constituents which seem to concentrate the medicinal properties of the plants themselves. They form what are sometimes called the active principles of the plants. They are also, and more commonly, known as the alkaloids. Thus, from the white poppy cultivated in Asia Minor, Egypt, Hindostan, and elsewhere, is extracted opium, which in turn contains a number of alkaloids, as morphine, codeine, narcotine, etc.; from Peruvian bark are obtained the valuable alkaloids quinine, cinchonine, etc.; from the St. Ignatius bean comes strychnine; from tobacco, nicotine; from coffee, caffeine, etc. The great value of many of these alkaloids, especially of morphine and quinine for medicinal purposes, has, as we all know, long been recognized. They have, however, been but little understood by chemists, and this has been a just reproach to chemistry. They have been studied carefully, better and better methods have been devised for their extraction and purification, but scarcely anything has been done until within a year or two past to clear up their inner nature. Their relations to simple substances were not known, and it seemed quite