Selected topics in colloid chemistry with especial reference to biochemical problems / by Ross Aiken Bortner.

  • Gortner, Ross Aiken, 1885-1942.
Date:
1937
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Licence: In copyright

Credit: Selected topics in colloid chemistry with especial reference to biochemical problems / by Ross Aiken Bortner. Source: Wellcome Collection.

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    almost every paper of Graham’s we find that he is investigating the phenomena of diffusion, and in following whole heartedly this one objective in all of its ramifications he uncovered fact after fact so that when the proper time came his conception of the colloidal state of matter rested upon a firm experimental foundation. This series of lectures is on the general topic of “Colloids in Biochemistry.” I believe the purpose of this initial lecture will be best served by calling attention to some remarkable comments which Graham made regarding colloid chemistry in general and especially the role of colloids in living processes. In 1830, when Graham was only 25 years old, he published a paper in volume one of the Quarterly Journal of Science6, entitled “The Effects of Animal Charcoal on Solutions.” This paper is an outstanding contribution in the field of adsorption. He notes that bone black had already been used to decolorize syrups in the process of sugar manufacture, but that hitherto the only study which had been made of bone black was to remove colored matters from solu- tion. He therefore studied the action of animal charcoal, de-ashed by boiling with dilute hydrochloric acid until silica only remained in the ash, and followed by complete washing to the absence of acid re- action, on a number of solutions, mostly of the inorganic type. In this paper he shows that such charcoal removes the blue color from ammoniacal copper solutions and that the copper could not be removed from the charcoal by subsequent elutriation with strong ammonia. He points out that silver is adsorbed from a solution of silver nitrate and that crystals of metallic silver appeared on the surface of the charcoal; that iodine was removed from a solution of iodine and potassium iodide and that the carbon could be dried at a relatively high temperature without iodine vapors appearing. If, however, the iodine-charcoal mixture were heated strongly in a closed flask the iodine could be resublimed, but later on cooling, the charcoal readsorbed the iodine vapors. He found that the charcoal adsorbed chlorine from a solution of the gas in water but that on the surface of the charcoal the chlorine was converted into hydrochloric acid. However, perhaps the most striking comment in this entire paper is his vision in that early period of chemical science, as to the effect of adsorption on procedures in analytical chemistry. He states: The same property is possessed by other solid bodies, in a state of minute division, as when newly precipitated, although not in so great a degree. And, in analytic researches, its interference must be guarded 6 Graham, Thomas. Quart. J. Sci., 1: 120-125 (1830).