IATROCHEM ISTRY (Gk. ia7p6c, iatros, ph•si cian). The first great iatrochemist was Para «dsus (14:)3-1541). who taught that the aim of chemistry was the preparation. not of gold. but of therapeutic agents. Adopting a view eur ient among, alchemists prior to his time, he held that. everything being composed of sulphur. mer cury, and salt, if the amount of any of these happens to rise above or fall below the normal in the animal body, the result. is a condition of disease. disease must be emnbated by chemical means. Paraeelsus therefore devoted himself t.o pharmacy and medical chemistry. and soon became famous through the many happy cures that he actually succeeded in effecting. Unfortunately the adventurous life that he led, and his gross lack of modesty, aroused suspicion in many, and the bitterest opposition among the more conservative members of the medical pro fession, and obscured his fame and greatly di minished the sphere of his influence. Neverthe less, his great work was accomplished : pure alchemy had received at his hands the first powerful blow, pharmacy had been firmly linked to chemical science, and medicine had been aroused from the torpor of many Following in the steps of Paracelsus came Turquet de Alayerne t1573-1655). Andreas Ulm: vius ( ?-1616). Oswald Croll, Adrian van Alyn sicht, and the great Van Belmont (1577-1641). Van HeImola not only realized that the processes of life, in health and disease. are largely dependent upon chemical changes, but he abandoned the ar bitrary assumptions of Paracelsus concerning the chemical basis of the animal body, and his keen experimental researches imparted a powerful im pulse to the development of scientific medicine. Equally, if not more, important was his recogni tion of the fact that there may he other gases than air, and that atmospheric air, carbonic acid. hydrogen. marsh and sulphurous acid may be quite different from one another. In cer tain special cases he also succeeded in showing that substances are not lost, either qualitatively or quantitatively, when they enter into chemical combination, and that they may be reobtained entirely from the resulting compounds. Yet he believed in the possibility of making gold, and among the absurdities found in his writings is the assertion—strange to relate—that mice may he spontaneously produced in buckets filled with soiled linen and wheat flour: But if the spirit of the time permitted such beliefs. so much
more wonderful must, appear the seientifie pene tration of his genius, so much more deserved is his place among the best names of both •hem istry and medicine. Other important names in connection with iatroehemistry are those of Syl vitt, (1614-72) and Taehenius. Svlvins was the first to grasp the similarity between the processes of respiration and combustion. and. rec..gnizing the Ii.tinetion arterial and venous blood, he understood that the bright color of the former was due to the action of air. Digestion, too, lie considered as a purely chem ical process. His pupil, Taehenius• was the first clearly to recognize that salts are substance: formed by the tution of acids and bases: he studied the composition and properties of many substances. invented a number of interesting qualitative tests. and even subjected a few re a•tion- to quantitative investipation, determin ing. for instance, the gain of weight involved in the oxidation of lead.
The age of iat•oebernistry marks a great, peri od in chemical history. During this period, for the first time. we find niftily thoughtful men making in endeavor to free themselves front the preconceived ideas of the past, and to approach nature in a critical spirit and with a curiosity purely scientific. With iatroehemistr• was thus horn the possibility of chemical progress. But this is not the only thing for which mankind is indebted to that period. ('or. while the iat•o chemists were preparing the first material for the very of future •hetnistry, others were busy developing industries which have since become affiliated to our science. Foremost among these men were Agricola, Palissy, and Glauber. Georg .Agricola t 1490-1555) rendered great services to mining and metallurgy• intro ducing rational scientific methods former and perfecting many of the processes of the latter. His splendid treatise on metallurgy. in which these processes were described for the first time.