The preparation and some properties of purified diphtheria toxoid / by Arthur Frederick Watson and Elsie Langstaff.
- Watson, A. F.
- Date:
- [1926?]
Licence: In copyright
Credit: The preparation and some properties of purified diphtheria toxoid / by Arthur Frederick Watson and Elsie Langstaff. Source: Wellcome Collection.
14/20 page 774
![The solutions at pH below the acid precipitation zone showed no floccu¬ lating value. At all hydrogen ion concentration levels which were definitely above the precipitation zone, however, flocculating values similar to those of the control purified toxoid were obtained. At as high a, pn as 10-0 the value remained the same, although the time of flocculation was considerably in¬ creased. This is rather a remarkable result in view of our old ideas with regard to the instability to acids and alkalis of unpurified toxin preserved with phenol. Moloney and Weld [1925] using unpurified toxoid at p^ 10-0 were unable to obtain any flocculation with antitoxins. The stability to shaking. During the preliminary survey of the chemical properties of purified toxoid the effect of shaking on the degree and time of flocculation with antitoxin was investigated and Table Ylll gives some of the results obtained. Table VIII. The stability of 'purified toxoid to mechanical shaking. Purified toxoid Shaken with Original Lf Period of shaking (hours) Lf after shaking C 4/26 Glass beads 33-34 3 33-34 C 4/20 99 7 3 5-6 C 4/22 A 99 18 3 14-15 C 4/18 Glass beads 14 3 14 (40 secs. TF) C 4/18 0-5 % phenol + glass beads 14 3 12 (1 day TF) C 4/18 0-5 g. charcoal + glass beads 14 O O 1 (i day TF) 25 cc. of the purified solutions were shaken vigorously in a mechanical shaker for 3 hours with and without the addition of phenol and charcoal. To ensure uniform shaking the same number of small glass beads were placed in each bottle containing the mixtures. Shaking alone may slightly affect the flocculating value but no appreciable diminutions have been observed. Shaking with 0-5 % pure phenol produces a slight drop in the flocculating value and the time of flocculation is considerably increased. That the active principle is adsorbed by charcoal is shown by the drop in the Lf value from 14 units to 1 unit after 3 hours’ shaking. The stability to rapid aeration. That solutions of purified toxoid are also comparatively stable to mild oxidation is shown by the fact that if a rapid current of air or oxygen is passed at room temperature through such solutions containing a small amount of capryl alcohol (to reduce frothing) for several hours, there is no loss of floccu¬ lating value. At temperatures approximating to 50° destruction is facilitated although the degree of destruction varies with purified toxoids prepared from different parent toxoids. The chemical properties of purified toxoids. Culture filtrates prepared from media made by the tryptic digestion of horse muscle consist of muscle extractives and breakdown products of the muscle split off by the action of the enzyme. An analysis of the nitrogenous](https://iiif.wellcomecollection.org/image/b30625385_0014.jp2/full/800%2C/0/default.jpg)
