Modern Toxicology.
Systematic and scientific investigation of alleged poisoning was scarcely known before the end of the eighteenth or the beginning of the nineteenth centuries. The advance of chemical and physiological knowledge, however, was soon applied to the more certain detection of the criminal use of toxic agents. Orfila’s “Traité de Toxicologie,” published in 1814, the result of a multitude of experiments, was the work which led the way in the establishment of exact tests. Dr. Swaine Taylor in England, Sir Robert Christison in Scotland, Casper in Germany, and a host of other medical chemists pursued the subject, and gradually toxicology reached an assured position. How slow was this attainment may be gathered from the testimony of an expert in a French murder trial in 1823 that globules of fatty mutton had been mistaken for white arsenic.
To Marsh’s arsenic test, made known in 1836, may be traced the practical fall of the poison which for so many centuries had reigned supreme among the deadly agents employed by the most cowardly but most dreaded of the tribe of assassins. The power of proving the presence of the metal which was afforded by the method then set forth brought out the chemical expert, and led to angry controversies. The skilled experimenter was apt to be very confident of his results, and naturally others who claimed to be as skilful as himself disputed his conclusions. Theories of the almost universal diffusion of arsenic were vigorously maintained, and on one occasion in France, in 1839, when Orfila had demonstrated the presence of arsenic extracted from the organs of the person supposed to have been poisoned, Raspail undertook to extract as much from the judge’s armchair.
Meantime the resources of the poisoners had been vastly extended by the discovery of the alkaloids. Many of these substances possessed extreme toxic power, and the invention of the means of detecting them was necessarily a gradual process. It was attained, though; and it may be asserted that at present either by chemical or physiological tests the recognition of the administration of any of the dangerous alkaloids is as certain as is that of the metallic poisons.
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.