LINXEA^ SOCIETY OF LOWDOX. 



79 



Both parents were cultivated by me in large numbers from seed 

 given me by de Vilmorin. To test their stability I have grown 

 large numbers without observing any than the usual modifications; 

 anyhow, I am sure that neither throws giants nor dwarfs. The 

 hybrid is bard to make, yet I obtained sufRcieut seed to raise a 

 first generation of more than IGOO individuals. This was very 

 lucky, because all, with the exception of a single plant, were 

 absolutely sterile. The one fertile plant was this in a very im- 

 perfect degree, one branch of it only producing seed. Trom these 

 seeds I could last year raise the second generation consisting of 

 imore than 20U0 plants. At first this second generation looks so 

 [much like the former that I thought to have obtained a stable hybrid. 

 lAs the plants grow older, however, and begin to flower and 

 [fruit, they show various combinations of characters derived from 

 liV'. prtHtnt/'rt/ffl and iV. nfs^ifrt. Yet the segregation is decidedly 

 ihard to recognise, partly probably because there is not much to 

 [segregate, and because also, as the sterility of the first generation 

 [shows, couibination is possible between a few only of the different 

 lldnds of reproduction-cells produced by the hybrid, partly because 

 Ithe characters themselves are hard to define. As a consequence 

 [of all this, one might really be excused if one mistook this second 

 jeneratiou for a species with only fluctuating variability. In this 

 [respect, it would therefore resemble (E. Lamarcliana, it this plant 

 iMere a hybrid. The curious point now is that it resembles 

 \(E. Lamarcl'iana in other respects, namely, it throws, like this 

 Iplant, giants and dwarfs in what one might call mutational 

 [numbers, as the photographs which I now beg to throw on the 

 [screen will show. Of course, this is not a case like (E. Lamarckiana; 

 [the giants here are due directly to the large stature of Nicotiana 

 Irustica, although they are even larger than this, but, if one did not 

 jknow its hybrid origin, the case would certainly be quoted as one 

 lof mutation. All this, I think, tends to show that CE. Lamarclciana 

 ns a hybrid, but as Heribert IVilsson in a very able paper has said : 

 I*' After all, for the question of the existence of progressive muta- 

 Ition, it is not of the first importance whether CE. LamarcMana is 

 la segregate from a specific cross ; the crucial point is, Is it a 

 jure genotype ? 

 Which in my nomenclature says — Is it a pure species ? 

 Now time fails to tell you of Nilsson's experiments ; you 

 ?^ili all have read them, and I think will agree with me that he 

 [has plainly shown that 07. Lamarclciana is not a pure species, but 

 [a mixtvire of different types. 



This makes (E. Lamarclciana absolutely unfit to serve as such, 

 las proof for the existence of progressive mutation, for nothing — 

 mo behaviour of chromosomes, however interesting this may be, 

 [and after Dr. Gates's careful investigations actually is — can let 

 [us make fall a particle of our claim that, to j^rove the existence of 

 [mutation, the purity of type from which the proof starts must 

 [be beyond the possibility of doubt. 



With the proof that (E. Lamarclciana is no pure species, the 



