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W.C. Roberts-Austen, says the Engineer, remarks that the importance of the isomeric and allotropic states has been much neglected in the case of metals.
We may get an idea of the nearly similar composition of the coal produced by very different plants or parts thereof, in remarking that as the cells, fibers, and vessels are formed of cellulose, and some of them isomeric, the difference in composition is especially connected with the contents of the cells, canals, etc., such as protoplasm, oils, resins, gums, sugars, and various acids, various incrustations, etc.
Brucine is a tertiary diamine, that is, formed by substitution in a double ammonia molecule. When distilled with potassium hydrate it yields quinoline, lutidine, and two isomeric collidines. The alkaloid atropine has been quite thoroughly studied with results of great interest.
If we suppose selenium to be merely modified sulphur, and phosphorus modified arsenic, how does it happen, we must inquire, that sulphuric acid and selenic acid, phosphoric and arsenic acid, respectively form compounds which it is impossible to distinguish by their form and solubility? Were these merely isomeric, they ought to exhibit properties quite dissimilar!
It sometimes happens that two compound substances differ in their chemical or physical properties, or both, even though they have like chemical elements in the same proportion. This phenomenon is called isomerism, and the generally accepted explanation is that the atoms in isomeric molecules are differently arranged, or grouped, in space.
Whether a practical commercial synthesis of quinine will follow is another matter, but it is within the bounds of possibility, or perhaps even of probability. It must not be supposed that no syntheses of alkaloids have been effected as yet. By heating butyl-aldehyde with alcoholic ammonia is formed paraconine, an alkaloid isomeric with the natural conine, but differing in physiological action.
In various colloidal substances, including the albuminoid, isomeric change is accompanied by contraction or expansion, and consequent motion; and, in such primordial types as the Protogenes of Haeckel, which do not differ in appearance from minute portions of albumen, the observed motions are comprehensible as accompanying isomeric changes caused by variations in surrounding physical actions.
Chemical analysis has led to the remarkable result, that fibrine and albumen contain the same organic elements united in the same proportion, i.e., that they are isomeric, their chemical composition the proportion of their ultimate elements being identical. But the difference of their external properties shows that the particles of which they are composed are arranged in a different order.
So also chemists have discovered that the same kind and the same number of chemical atoms may be arranged in different ways and thus become entirely different things in their properties, though the materials are unchanged; such "isomeric compounds" are among the most interesting of modern chemical discoveries; the arrangement of similar atoms under different ideas gives different bodies.
Chemists have discovered the art of building them up from the simpler to the more complex, and do not doubt that they will eventually produce the most complex. Moreover, the phenomena attending isomeric change give a clue to those movements which are the only indications we have of life in its lowest forms.
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