“Degrees of susceptibility to diptheria toxin among guinea-pigs. Transmission from parents to offspring”

Abstract

The author called attention to the usefulness of the antitoxin unit furnished by the Institute for Experimental Therapy under the direction of Professor Ehrlich in the routine testing of the strength of diphtheria antitoxin. The one uncertain element is the relative resistance of the guinea-pigs to diphtheria toxin.

In the course of the past nine years the author has given considerable personal attention to this subject and found that different dealers furnished guinea-pigs of slightly different susceptibility. This difference was attributed to environment and care. The animals bred under the author's supervision generally showed maximum resistance. Irregularities in the routine tests during the past year led the author to look up the genealogy of the pigs used and he found that the different degrees of resistance belonged to certain families or litters and were constant for those families. Thus, one mother gave birth to young which did not react to what was the usual fatal dose. Four successive litters possessed the, same resistance. As each pig could be tested but once the, precise degree of resistance could not be measured, but it appeared probable that this family could stand 40% more toxin when mixed with the antitoxic unit than those of average susceptibility. Other mothers were traced whose offspring possessed less resistance than the ones described, but could still neutralize 20% more toxin when mixed with the antitoxic unit than the average.

It would seem from these observations that different degrees of susceptibility to toxin are to be found among guinea-pigs and that the special degree possessed by any one is not to be attributed to individual variation, but to a family trait or character. The resistance in the cases cited could not beattributed to any preliminary treatment with toxins and antitoxins. Experiments are now under way to determine the part played by the male in the transmission of toxin resistance. In the case of the most resistant family, the four litters were the offspring of two males.