522 WHITE: ORIGIN OF SPECIES 
Again, Professor de Vries found that some of his newly mu- 
tated species of Oenothera were themselves immediately mutable. 
My observations of the mutation from Lycopersicum esculentum to 
L. solanopsis seem to indicate that the mutative act was coincident 
with impending varietal senility in the Acme variety, and that the 
resulting variety, the Washington, has no tendency to. mutate. 
Doubtless LZ. esculentum originated by mutation from some other 
pecific form of that genus, but no evidence seems to be obtainables 
that, although variable, it began to be really mutable until many 
years after the species became horticulturally known. These facts 
indicate that in some species the mutative period occufs in base 
part of their time-existence, and that in other species it occurs 1 
another part of the same. 
Some of the observations made by myself in the cases of mu- 
tation of Lycopersicum are thus seen to be different from any of 
those made by Professor de Vries in cases of mutation of Oeno- 
thera ; but the facts which we have both observed are not in — 
flict. Their differences only indicate that the field of investigation 
which that distinguished botanist has opened in close contact with 
nature is a very broad one. 
SMITHSONIAN INSTITUTION, 15 July, 1902. 
