Nucleic acids : their chemical properties and physiological conduct / by Walter Jones.
- Jones, Walter, 1865-1935
- Date:
- 1920
Licence: In copyright
Credit: Nucleic acids : their chemical properties and physiological conduct / by Walter Jones. Source: Wellcome Collection.
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![From an optical examination of the nucleic acids of thymus, pan- creas, and spleen, the following observations have been made (Jones [1908]): 1. Solutions of the sodium salts of all three nucleic acids have the same optical rotation in any given concentration. 2. The optical rotation varies with the concentration and accord- ing to the same law in the case of each nucleic acid. 3. The variation in rotation by dilution with ammonia is different from that by dilution with water, but is the same with all three nucleic acids. 4. The variation in rotation by dilution with acid obeys still a third law, and here again the three nucleic acids behave alike. 5. The variation in rotation by dilution with any solvent is parallel to a variation in the viscosity of the solution. In this re- spect also the three nucleic acids are scarcely distinguishable from one another. The actual identity of two complex chemical substances can never be proved, but one may come to a point where it is unprofitable to make further comparisons. It would seem that this condition has been reached with animal nucleic acids when a prominent contributor suggests that the designation of animal nucleic acids by the names of the glands from which they are obtained is as superfluous as would be the application of a similar nomenclature to lecithin (Steudel [1908]). It is therefore necessary to discuss only two nucleic acids in order to have an understanding of them all. The Final Hydrolytic Products of Nucleic Acids. Thymus nucleic acid was first chemically examined by Kossel and Neumann [1893]: [1894, 1]. Kossel had previously found that nucleic acids of different origin are markedly different from one another in respect to the relative quantities of the purine bases which they yield on hydrolysis [1894]: [1891]. Yeast nucleic acid had been found (as Kossel supposed) to yield four of these com- pounds, guanine, adenine, xanthine and hypoxanthine, but Kossel and Inuko [1894] had obtained only three purine bases from the nucleic acid of steer sperm. Now most unexpectedly Kossel and Neumann find only adenine among the hydrolytic products of thymus nucleic acid. Thinking it improbable that so large a number of nucleic acids actually exist in animal and plant tissues as the supposed facts indicated, Kossel and Neumann assumed that there are in fact but four nucleic acids each of which yields a single purine base, and](https://iiif.wellcomecollection.org/image/b29807499_0023.jp2/full/800%2C/0/default.jpg)
