Standardization of anti-dysentery (shiga) serum / H.J. Sudmersen, B.F. Runge, and R.A. O'Brien.

  • Südmersen, Henry J.
Date:
[1924?]
Catalogue details

Licence: In copyright

Credit: Standardization of anti-dysentery (shiga) serum / H.J. Sudmersen, B.F. Runge, and R.A. O'Brien. Source: Wellcome Collection.

    6/10 (page 103)
    which, when mixed with 0'025 c.c., our test dose of antitoxin, would cause 100 per cent, of deaths, and those causing approximately 20 per cent, of deaths. The intervals between the doses are much wider than in standardization tests of diphtheria and anti-tetanic sera; the “ error of the test” is of a different order. But with this reservation there is a satisfactory degree of agree¬ ment between the results obtained by two investigators working independently. In the final column are shown the percentages that would have resulted if the period of observation of the mice had been limited to four days, and all mice living after that time had been considered as survivors. We consider it preferable to adopt seven days as the limit of observation. Results of intravenous injection into rabbits (Tables IY and Y).—It was unfortunately impracticable during these experiments to obtain rabbits of a standard weight. It proved in practice to be more convenient to use whatever Table IV.—Minimum Lethal Dose Shiga Antigen A A. (Intravenous Injection : Rabbits.) Amount of toxin in mgm. 0*05 0-025 0-015 0-01 0-005 Number dying. 2 2 0 0 0 Number living. 0 1 2 2 1 Table V.—Toxin {Shiga) AA against Antitoxin (7.950. {Intravenous Injection: Rabbits. Antitoxin (7.950, 0'025 c.c. constant.) Amount of toxin in mgm. Number dying. R. S. Number living. R. S. 0-2 0-175 0-15 0-1 0-075 0*05 0-025 2 — . 0 1 — . 1 5 8 . 4 3 9 . 6 0 1 . 3 0 — - 0 — R and S indicate two observers working independently. 1 2 5 4 1 rabbits were available and to give the desired dose of toxin without making any allowance for weight. We should have preferred to use rabbits of 1500 gm. for all experiments, but those that were available varied in weight from 1400 to 2500 gm. It is probable that our practice of making no allowance for weight is at least partly responsible for the small difference between the results of the two workers shown in Table V. It will be noted that one worker found that 0T5 mgm. of toxin AA when mixed with 0'025 c.c. of standard antitoxin and injected would kill 8 rabbits out of 9, whereas the other found only 5 out of 9. When using a dose of 0T mgm. of toxin, one worker found that 9 out of 11 rabbits died, whereas the other found only 3 out of 9.