Page:The New International Encyclopædia 1st ed. v. 04.djvu/649

CHEMISTRY. 567 alchemy had received at his hands the first jiowcrlul blow, j)harmacy had been firmly linked to chemical science, and medicine had been aroused from the torpor of many centuries. Following in the st^ps of Paracelsus came Turquet de Mayenie (1573-10.55), Andreas I^iba- vius ( ?-lGlli),* Oswald CroU, Adrian van Myn- sicht, and the great Van Hehnont (1577-1044). Van Helniont not only realized that the pnK'Csses 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 meVlicine. Equally, if not more, imi)ortant was his recogni- tion of the fact that there may be other gases than air, and that atmospheric air, carbonic acid, hydrogen, marsh gas, and sul])hurous 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. Vet 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 be spontaneously produced in buckets filled with soiled linen and wheat flour! But if the spirit of the time permitted such beliefs, so nuich more wonderful must, appear the scientific pene- tration of his genius, so much more desened is his place among the best names of both chem- istry and medicine. Other important names in connection with iatrochemistiy are those of Syl- vius (1614-72) and Tachenius. Sylvius was the first to gi"asp the similarity between the processes of respiration and combustion, and. recognizing the distinction between arterial and venous blood, he understood that the bright color of the former was due to the action of air. Digestion, too, he considered as a purely chem- ical process. His pupil, Tachenius, was the first clearly to recognize that salts are substances formed by the union of acids and bases; he studied the composition and properties of many eubstances. invented a number of interesting qualitative tests, and even subjected a few re- actions to quantitative investigation, determin- ing, for instance, the gain of weight involved in the oxidation of lead. The age of iatrochemistry marks a gi'eat peri- od in chemical history. During this period, for the first time, we find many thovightful men making an endeavor to free themselves from the jtrcconceived ideas of the past, and to approach nature in a critical spirit and with a curiosity purely scientific. With iatrochemistry was thus bom the possibility of chemical progress. But this is not the only thing for which mankind is indebted to that period. For, while the ialro- chemists were i)reparing the first material for the very foundation of future chemistry, others were busy developing industries which have since become affiliated to our science. Foremost among these men were Agricola, Palissy. and Glauber. Georg Agricola (1490-1555) rendered great services to mining and metallurgj". intro- ducing rational scientific methods into the former and perfecting many of the processes of the latter. His splendid treatise on metallurgj-, in which these processes were described for the first time, CHEMISTRY. long remained the standard work on its subject. Besides, he introduced a practical system for the classification of minerals, based on their physical properties, such as color, hardness, etc, Bern- hard Palissy (c.1510-8!)) , considering worthless and ridicvtlous the efforts of alchemy, devot«d himself to experimental research in ceramic art, and invented a number of valuable methods of coloring and enameling articles of pottery. Johann Rudolf Glauber (1C04-08) improved many processes of dyeing, and prepared a num- ber of useful salts, including so<lium sulphate ('Glauber's salt"), the chlorides of zinc, tin, ar- senic, copjier, lead, and iron, the nitrate of am- monium, tartar emetic, etc. He even succeeded in gaining some insight into the rationale of cer- tain processes: but this did not prevent him from adhering to the most fanUistic absurdities of alcliemy to the very end of his life. In con- nection with the iatrochemical period, reference must finally be made to the wonderful develop- ment of the art of making articles of glass, and to the rapid progress of the liquor industry, which had only Ijeen founded toward the end of the Fifteenth Century — i,e, a short time before the commencement of the period. As to scien- tific pharmacy, we have already stated that its beginning coincides with that of iatrochemistry, and it is hardly necessary to add that the latter enriched it with many new jjreparations. and with a knowledge of the medicinal properties of substances already known. About the middle of the Seventeenth Century, iatrochemistry came to a sudden decline. That this had to happen sooner or later is clear, if we consider that a true medical chemistry could not possibly flourish before, on the one hand, chemistry itself was placed on a sound basis, and before, on the otiier hand, anatomy and physiology had attained a stage of serious de- velopment. The iatrochemists had evidently misdirected their efforts, and if we should in our present structure of chemistry mark the ])arts established by them, we would find that their lasting contributions were very few. The his- torical importance of the period is chiefly in the fact that with it came a revolution against tra- ditional errors and a change in the direction of research. The FoRERt'xxERs or Chemistry. In the Seventeenth Century we find the Englishman Robert Boyle (1027-91) grasping truth with an insight unprecedented, and in many respects not yet surpassed. Boyle understood that chem- istry mnst be treated as an independent science — i.e. primarily without reference to applications of any sort, and that only in this, m.inner could the relationships between chemical phenomena proper be discovered. He maintained that chem- ists should consider as an element only a sub- stance which, in spite of exliaustive actual ef- forts, they have not succeeded in decomposing. And even this method, though necessary and suf- ficient for the purposes of science, he did not re- gard as proving the elementary nature of a sub- stance absolutely beyond doubt. Still, he was inclined to consider the metals as elements, and, proving experimentally that the products of the destructive distillation of wood are compound, he refuted the opinion — then generally prevalent — that dry distillation breaks up substiinces into their elements. He further defined the distinc- . tion between a chemical compound and a mix-