26o LOTSV'S THEORY OF l^'OLUTION. 



Only sexual reproduction, that is, crossing, brought together the 

 "genes" of different primitive organisms, and thus created the basis for 

 higher development and progressive formation of species. 



It will be seen from these statements that Lotsy means by 

 his s]iecies the so-called " petites especes " of Jordan.* I have 

 already on a previous occasion pointed out that it is not advisable 

 to retain the names " species " for these units, since the term 

 ordinarily is used in a much wider sense. They should rather 

 be called Jordan's units, and the term " species " should be used 

 in the usual sense. 



Lotsy's theory to a certain extent resembles Nageli's ortho- 

 genesis. Given certain primitive organisms, and a thorough 

 Ivuowledge of them, and the trunk and tusks of an elephant can 

 "be predicted from them with mathematical necessity provided 

 the circumstances permit of their formation ; with the same 

 necessity arise the brain of man, the stinging hairs of nettles, 

 the tendrils of the vine, and millions of other developed Anlagen, 

 Stated in this almost brutal nakedness, the theory appears 

 absurd at sight. That my way of putting it is not unjustified 

 follows from Lotsy's own words. Thus, on page 371 he writes : 



The "gene" (Aiilagc) for legs can, r..?., very well have been present 

 already in an evertebrate animrd, but has only been able to come into 

 effect after it had come by crossing into an organism with the "gene" 

 of a vertebral column. This organism can either have had formed 

 already the vertebral column or may still he evertebrate when it was still 

 without the " gene " on which the " gene '" for a vertebral colunm has 

 to act. Thus, both " genes," that for a vertebral column and that for 

 legs, may be present in an evertebrate animal. 



In other words, according to this theory, the " genes " for legs 

 and vertebr?e may already be in amoebas. This is more easily 

 asserted than disproved, but to my mind nothing wilder was ever 

 propounded by the exponents of the much-ridiculed German 

 NatitrpJiilosophie of about a hundred years ago. On the one 

 hand the primitive organisms are supposed to be so very simple ; 

 •on the other hand they are supposed to contain already certain 

 peculiarities (by whatever term we may designate them), which 

 include the germs of the countless specific characters of higher 

 plants and hig^her animals 



At the same time, I do not at all agree with the view that 

 the simplest organisms are as simple as they are usually repre- 

 sented. In fact, having followed carefully the recent discussion 

 of the possibility of creating artificially living beings, I was 

 simply amazed at the fact that prominent men lead their 

 authority to the belief that this may be possible. Haagedorn,f 

 at all events, expresses this very cautiously as follows : 



I do not think the possibility is excluded of creating " living " organ- 

 isms by a combination of not-living things, like the "filterable viruses" 



* Or. more strictly speaking, Johannsen's pure lines. 

 t " Vortrage und Aufsiitze iiber Entwicklungsmechanik der Organis- 

 men herausgegeben von Roux," Heft 12. 



