Nucleic acids : their chemical properties and physiological conduct / by Walter Jones.

  • Jones, Walter, 1865-1935
Date:
1920
Catalogue details

Licence: In copyright

Credit: Nucleic acids : their chemical properties and physiological conduct / by Walter Jones. Source: Wellcome Collection.

    14/168 (page 2)
    Even at present the terms nuclein and nucleoprotein suggest some- thing a little disquieting, but all difficulty disappears when the original sources of these terms are examined in the light of modern discovery. In the year 1868 Friedrich Miescher [1868] undertook a chemical examination of pus cells. Surgical bandages, secured from a neigh- bouring clinic, were extracted with a dilute solution of sodium sulphate, and the heavy pus cells thus obtained were easily separated from ad- herent serum and salt solution by careful decantation. The cells, still intact, were then submitted to the digestive action of artificial gastric juice which dissolved the protoplasm, leaving the more resistant nucleus as an insoluble grey powder, so that cell nuclei free from protoplasm became available for chemical study. Upon treatment of these insoluble nuclei with dilute sodium carbonate a solution was obtained in which acetic acid produced a flocculent precipitate which was found to contain phosphorus and responded to protein colour tests. This substance, to which Miescher gave the name nuclein on account of its origin, was the first known member of what is now a comparatively large class of sub- stances obtainable from the nuclei of animal and plant cells. Hoppe- Seyler [1871] prepared one from the nuclei of yeast cells, and Kossel [ 1881] afterwards prepared another from the red-blood corpuscles of birds. All of these nucleins are insoluble acids which form soluble sodium salts. They respond to the protein colour reactions, but differ from proteins in the phosphorus which they contain and in the resistance which they offer to the solvent action of artificial gastric juice. Shortly after the completion of his work with pus cells, Miescher removed from the laboratory of Hoppe-Seyler in Tubingen to assume control of the department at Basel where he became intensely inter- ested in the life of the Rhine salmon in fresh water (see Miescher [1897]). He was able to prove the older suspicion that these animals never partake of food in their ascent of the Rhine from the sea to the spawning beds; for with rare and easily explained exceptions the alimentary canal was found free from food detritus, and the digestive fluids were as a rule inactive. As the muscle tissue had greatly de- creased during the Rhine journey, while the organs of reproduction had grown enormously, it is necessary to conclude that eggs and sper- matozoa had been formed from muscle protein. During the spawning season the spermatic fluid or laclismilch can be obtained from these fish in great quantity, and when expressed from the vas deferens of a living fish, consists of little more than spermatozoa suspended in a dilute salt solution. The spermatozoa are composed of head, tail and middle part, it being especially