150 BOTANICAL GAZETTE [FEBRUARY 
the hybrid ee was wrapped around, so to speak, by an epidermis 
of purpureus.” Very recentl as reinvestigated Laburnum 
Adami,” and has brought additional evidence to show that Baur’s view is 
correct. Finally, WINKLER, in his latest paper, states that a study of his 
Solanum forms from BAur’s viewpoint discloses that for the most part they 
are, as BAuR thought likely, periclinal chimeras. Here he suggests that what 
have been taken to be graft hybrids may (theoretically) be actual graft hybrids, 
resulting from the fusion of the somatic cells of different species; or again they 
may have a hybrid nature, owing to the migration between stock and scion 
of various substances (as atropin or nicotin in the Solanaceae); or finally 
they may be chimeras, where the possibility lies open that they may be byper- 
chimeras, sectorial chimeras, or periclinal chimeras. Careful cytological study 
has shown that Solanum tubingense, S. proteus, S. Koelreuterianum, and S. 
Gaertnerianum are periclinal chimeras. S. tubingense has a nightshade body 
and a tomato epidermis; S. Koelreuterianum has the reverse relation of the 
two components; S. proteus has a tomato periphery of two cell layers, and it 
is probable that S. Gaertnerianum has the reverse relation. WINKLER thinks, 
however, and the cytological evidence noted is confirmatory, that in Solanum 
Darwinianum he has a true graft hybrid that was produced by the fusion of 
vegetative cells of the nightshade and tomato. If this is proven to be correct, 
it will stand, not only as the first experimentally produced graft hybrid, but as 
the only certain instance on record of such a form. The discoveries of WINK- 
LER and Baur open a new path in experimental biology, and to one as much 
as to the other belongs the credit that goes to the pioneer; to WINKLER, 
because his brilliant work has made possible the experimental study of these 
problems, and because his studies mark the opening of a new line of investiga- 
tion; to Baur, because he has solved the riddle of nearly a century, and because 
he nas made possible the interpretation of WINKLER’s results. It goes without 
saying that biologists will wait with eager expectancy the announcement of 
new results, and oe many experimenters will be attracted to the new field — 
Henry C. Cow.e 
The cto aspect of graft hybrids and chimeras may be summarized 
as follow 
In t ee and 1907, in papers dealing with the rdéle of the chromosome in 
heredity, STRASBURGER™ included an account of his investigations upon 
™ BUDER, gen Studien an Laburnum Adami. Ber. Deutsch. Bot. Gesell. 
28:188-192. 1 
13 Wierie. Bike Ueber das Wesen der Proptbastarde. Ber. Deutsch. Bot. 
Gesell. 28:116-118. 1910, 
4 STRASBURGER, E., SoS ga Beitrige zur berate ae 2 I. Typische 
und allotypische ‘cacoectaie: Jahrb. Wiss. Bot. 42:1—70. fl. 905. 
die Individualitit der Chromosomen a ‘die Propfhybriden- 
Frage. Op. cil. 44:482-555. pls. 5-8. 1907. 
