51�Թ�

No serious observer, acquainted with modern microscopic technical methods, has been able to confirm the explanation of their observations given by the few modern believers in heterogenesis.

On the basis of such experiments Korschinsky developed the theory which had been proposed by Koelliker in Wuerzburg thirty years earlier, namely, the theory of "heterogeneous production" or "heterogenesis," as Korschinsky calls it.

From time to time there have been observers who have maintained a belief in the opposite theory, to which the name heterogenesis has been given.