About the year 1870 a new complication occurred when an Italian chemist named Dr. Selmi proved that putrefactive animal matter and certain bacteria yielded alkaloidal products, often poisonous, to which the name of ptomaines was given. Selmi was engaged as an expert in the investigation of a case in which it was suspected that an individual had been poisoned. A product was obtained, apparently an alkaloid, but which Selmi could not identify with any known vegetable substance. He came to the conclusion that it was of animal origin, and after a long series of experiments he proved his theory. Several eminent toxicologists at first asserted that ptomaines could be distinguished from vegetable alkaloids by the property of yielding Prussian blue with ferric salts. This test, however, proved fallacious as several series of vegetable alkaloids, notably the pyridic and the allylic, gave the same reaction. The distinction between animal and vegetable alkaloids is a delicate one, and has to be established by an accumulation of chemical evidence. Leucomaines, which are also alkaloidal products, are distinguished from ptomaines by being formed in the body from living tissues, as a result of their activity. These were first separated by Armand Gautier in 1886. Their constitution is more complex than is that of the ptomaines, but they are not generally of a poisonous character. XXIII PHARMACY IN THE NINETEENTH CENTURY “The advance in every section of chemistry during this century (the 19th), and especially during the latter half of it, has literally been by leaps and bounds. Although practically a creation of our own time, no branch has been more fruitful in result, in suggestion, or in possibility, than that of organic analysis.” (SIR THOMAS E. THORPE:--“Essays in Historical Chemistry,” 1894.) Three great achievements characterise the pharmacy of the nineteenth century, namely, the discovery of alkaloids in its early years, of anæsthetics in the middle period, and of synthetic organic products in its later years. ALKALOIDS. The alkaloids extracted from vegetables are the ideal quintessences which the alchemical pharmacists of the sixteenth and seventeenth centuries sought so eagerly to obtain. Their characteristic property is that they are basic, that is, that definite salts can be formed from them by combination with acids. They all contain nitrogen, and have an alkaline reaction.