The theory that individuals suffering from tuberculosis transmit to their offspring a predisposition to a similar infection seems to have established itself firmly. If this theory be accepted, the proposition that these individuals at the same time transmit a partial immunity, or at least an increased power of resistance to this infection after it has been acquired, seems at first glance rather paradoxical. Yet in recent years a number of observers have taken the position that the children of tuberculous parents possess a degree of protection against this disease which results in a favorable outcome more frequently than may be hoped for among patients whose parents were more fortunate. Numerous statistical studies intended to support this theory have been published since Reibmayr1 directed attention to the subject in 1892.
So many factors are to be considered in determining the truth of this question that it is difficult to present