HYBRIDISING OF MONSTROSITIES. 69 
HYBRIDISING OF MONSTROSITIES. 
By Professor Hugo DE VRIEs, 
University of Amsterdam. 
THE well-known hypothesis of Darwin with regard to the material trans- 
mitters of hereditary qualities, called Pangenesis, assumes that each 
particular quality is determined by a special transmitting body. This 
theory forms, in point of fact, though this is often overlooked, the scientific 
foundation of the speculations regarding heredity now so much in vogue. 
And in order to obtain starting points for experimental investigation in 
this branch of study, it is always best to return to the actual basis of the 
theory, since, as Mr. Galton says in his “ Hereditary Genius,” “ it gives a 
key that unlocks every one of the hitherto unopened barriers to our com- 
prehension of the nature of heredity.” * 
In connection with the teaching of Quetelet and Galton regarding the 
laws of continuous variability,t Pangenesis leads to the conviction that 
new distinctive features arise, not through this, but discontinuously. It is 
a question, it is true, of very small steps, but nevertheless they are steps, 
and not a gradual improvement of existing characters, as with the 
origination of races. 
One very important result from Pangenesis appears to me to be that 
one and the same quality in various organisms depends upon the presence 
of the same material bearer.$ 
Such material unities may therefore be transferred from one species to 
another by means of hybridising. Thence must arise hybrids which 
would be just as stable as ordinary species, and which therefore, in certain 
cases, could imitate normal species. 
If the literature of Hybridity be examined with regard to this question 
two facts present themselves. One is that a number of cases are men- 
tioned which should be classed under this head ; and the other, that very 
little is known of the way in which such a transferring of characters 
takes place. 
In horticultural practice, especially, there have frequently been trans- 
ferred with good results certain peculiarities in newly discovered or 
newly imported species into existing hybrid races. The genera Gladiolus, 
Caladium, and many others afford examples. In scientific trials also new 
and constant forms of mixed character have frequently been obtained by 
hybridising; as, for instance,'by Lecoq with Mirabilis, and by Godron with 
Datura and Linaria. Focke, however, emphasises the unsatisfactory 
nature of our knowledge in this direction in his splendid work on 
nf PManzenmischlinge ” (, 484). As is well known, stable hybrids are 
the result of the experiment ; but of how it is done, how the transfer of 
the peculiarities is effected, we know as yet very little. 
Professor Le Monnier, of Nancy, has recently observed a very re- 
markable case, and I am indebted to his kindness for the possibility of 
* F. Galton, Hereditary Genius, p. 364. 
+ Bateson, Materials for the Study of Variability. 
t “Unity and Variability,” The University Chronicle, Berkeley, California, 1898. 
§ Intracellulare Pangenesis, Jena, 1889 
