398 LOTSY, CURRENT THEORIES OF EVOLUTION. 
was not caused directly by it but indirectly only in as much as 
hybridization merely stimulated that mysterious property of living 
‘matter: variability. After MENDEL’s classic work, this view is 
however untenable. MENDEL proved, beyond doubt, that the direct 
cause of the diversity after crossing was hybridization and nothing 
but hybridization. But MENDEL’s work remained unnoticed until 
almost forty years after its publication. This was not due, as is 
frequently supposed, to it having escaped the notice of men, who 
should be considered to be capable judges, because we now know 
that MENDEL’s work was known to FOCKE, GALTON, KERNER VON 
MARILAUN and NäGELI. 
What then was the cause of the disregard of MENDEL’s work ? 
In the first place, that it was expressed in mathematical terms, 
which could not be interpreted biologically at atime when nothing 
was known about the existence of chromosomes. Consequently this 
mathematical accuracy made so little impression, on even so com- 
petent a judge in matters of hybridization as Focke, that he merely 
states that MENDEL obtained essentially the same results as KNIGHT 
long before him, but that he believed to have found constant 
numerical relations between the different types obtained. 
In the second place that MENDEL had the misfortune to run up 
against KERNER VON MARILAUN and NäGELI, two authorities, who 
both wereconvinced to have obtained conclusive evidence that species- 
hybrids were constant, so that MENDEL’s results obtained from 
crosses of gardenpeas, even, if correct, could not have any general 
bearing. 
Moreover MENDEL’s not being a biologist, has probably played a 
role also in the disregard of his work. NäGELI’s disregard at least 
can hardly be explained in any other way than by assuming distrust 
of results obtained by an inmate of an out of the way monastery, 
of whom nobody had previously heard. Yet MENDEL had sent to 
NäGELI a number of packages of his hybrid seeds with precise 
predictions as to the characters of the plants to be raised from 
them. NäGELt, unfortunately, trusted the sowing of these important 
seeds to one of his gardeners and apparently took very little further 
notice of them. He had too much evidence, which to him seemed 
to be conclusive, that the hybrids he was best acquainted with: 
those of Hieracia were constant. 



