On neurokeratin / by W. Kühne ... and R.H. Chittenden.

  • Kühne, W. (Willy), 1837-1900.
Date:
1890
Catalogue details

Licence: Public Domain Mark

Credit: On neurokeratin / by W. Kühne ... and R.H. Chittenden. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

    13/54 (page 9)
    layer. Boating on the acid fluid, thai the latter only Deeded to be drawn off and the operation repeated with fresh dilute acid and water. When tlii^ had been continued until a portion of the aqueous fluid was not rendered tnrbid by a large excess of alcohol, the pasty like mass under the ether was drawn off, mixed with alcohol until it could be easily filtered, boiled with 60-per-cent. alcohol for half an hour, and filtered on a hot-water funnel. The filtered fluid, at first clear, quickly became milky on cooling from the sepa- rated cerebrin. The brain residue was then repeatedly boiled with absolute alcohol, benzol, and chloroform, the filtrations being made with the aid of the hot-water funnel. In order to remove the nuclein from the much-shrunken preparation, it was treated for several days with about two litres of one-per-cent. sodium hydroxide solution, filtered, washed with the alkali until the washings were not rendered turbid by acid, then with dilute hydrochloric acid. Finally, the residue was boiled with alcohol containing a little hy- drochloric acid, then with the various solvents for the mye- line bodies, and at last thoroughly washed with ether. Whether it is possible by either one of the above meth- ods to prepare larger quantities of neurokeratin pure is un- certain. We need to remember, in considering the prepara- tion of this substance, that we are dealing with a body which can not be dissolved unaltered and then reprecipitated, but with one which can only be obtained as a residue, and, fur- ther, that, in spite of great patience, we have not been able, as before mentioned, to entirely remove the myeline bodies. A further difficulty is to be found in the visible admixture of insoluble pigments, for neurokeratin obtained from thegraa substance, or from the entire brain, has a distinct yellowish color, while that prepared from the white substance is color- less. Another slighl impurity is to be found in the presence of paper fibers, although we have avoided these as much as