88 PROCEEDl^S'GS OF THE 



pi'eceding liis writing, and then muoh less attention was paid to 

 these questions than now. Eeeentlj Brainerd, for example, has 

 descrd)ed no less than 75 certain hybrids in a single tribe 

 ot' Viola alone. 



After thus having given uiv objeLtions, I may be allowed to call 

 your attention to some of the 



Advantages. 



In the first place, the circumstance, that a group of new 

 species arises simultaneously, and 77ot one species /*-o?n the other, 

 simplifies matters, inasmuch as we need not look for intermediates 

 between all these species — they never were chains. Of course, I 

 do not mean that no species in the group have been exterminated, 

 but they were no transition forms. This explosion-like appear- 

 ance, furthermore, seems to me much more in accordance with 

 what we find in Palaeontology than a very slow transformation 

 from one species to another. The point urged, that the intro- 

 duction of a major factor can cause considerable change, explains 

 Avhy we find no transitions between great phyla, and makes their 

 great antiquity better understood. So it is quite easy to see how 

 Angiosperms cau — as geological evidence, so far as it goes, shows 

 ns — have appeared very quickly in very different forms. The 

 great diversity of new species which can arise from one cross 

 makes it, furthermore, simpler to comprehend how, without any 

 slow process of adaptation, forms can arise fitted to live miderthe 

 circumstances in which they are born. They arise ready-made, 

 survive if they fit, die if they do not. Another advantage to my 

 mind is that it opens the possibility to regard the origin of species 

 in the same way as at the origin of chemical compounds, and thus 

 brings further evidence for the assumption that similar laws 

 reign over lifeless and living I^ature. In this respect, I want to 

 Jay special stress on the fact that I do not, as de Vries did, 

 consider the factors or gens as living particles, but as chemical 

 substances not living themselves, but the result of -whose inter- 

 action is what we call life. In this respect, as in many others, I 

 perfectly agree wath Hagedoorn. I think that recent investigations 

 tend to support this view. In the laboratory of Kamerlingh 

 Onnes in Leiden, Becquerel has kept immersed in liquid air 

 during six weeks small glass tubes containing, in a vacuum as 

 high as could be obtained, decorticated seeds of Medicago saliva 

 and of mustard, and spores of different kinds of mould and 

 bacteria. After this these same tubes Mere immei'sed in liquid 

 hydrogen for 77 hours. The seeds, moreover, were kept during a 

 year and a half in the vacuum-tubes, the spores and bacteria even 

 two years. Tet the}'- sprouted ! 



In these experiments, which united for the first time an extreme 

 desiccation, an extreme lack of air, and very low temperature, even 

 dow'n to 253° below zero centigrade, the protoplasm, deprived of 

 Avater and oxygen, and under hardly any atmospheric pressure, 

 must have lost its colloidal stage, and cannot have shown a trace 



