117 



Bufc, tliis can be accepbed only in the case where one believes that species 



are fortned only through the fixation of characters acquired by adaptation or 



direct influence, which characters are ever diverging. When we think of 



several othar causas of the forrnation of spacies, such as cro33ing and mutation, 



we can not but be forcad to conchide that it is imposaible to arrive at blood - 



affiuity through indirecfc methods. Th3 latfcer conchision can be easily under- 



stood by one who accapfcs the pai'fcicipation theory. It is only in some special 



case that we can see blood - relationsliip through the sfcudy of resemblanca'^. 



As blood - relationship is of course one of the natural relations mauifested by 



organisms, it should cerfcainly appaar in one phase of the dynamic sysfcem. 



Bufc, ifc can nofc be definitely stated that blood - relationship is the only criterion 



for coustituting a natural sysfcem. Engler goes on to say'' : 



Es hat die Erfahrang gelehrt, daB atiBerlich oft aihi Jthnliche Organismen ntir 

 eine entfemte Verwancltschaft besitzen. 



This is indeed true. That is why I should say tliat a real natural relation 



is so and so iu external form, but at the same time is manifested differently 



in blood - relationship. In this respacfc, his opinion diifers from mine. Again 



he says^^ : — 



So ist man zxi der Erkenntnis gelangt, daB einzellige, kiigelige, also iluUerUch sehr 

 Rhnliche Organismen nicht bloB sehr verschiedenen Familien, sondem auch verschie- 

 denen Klassen und Abteihingen angehoren konnen. 



In my opinion, this will not do. According to my idea, if organisms are very 



similar in their external forms, they should be taken into the same group. 



In some spacial case where we know their blood - relafcionship exacfcly, ifc will 



be all righfc to arrange thetu according to tliis criterion. The latter arrangement 



is sometimes, as Engler states above, very different from that made according 



to the standard of external forms. But this does no harm to our natural 



system. The difference follows from the difiference in the criterion. The 



natm-al system should, therefore, be a dynamic one wliich manifests diflferenfc 



phases when viewed from different standpoints. Furfcher he proceeds to 



say: 



So gelangt man zur Feststelhmg von Verwandtschaftskreisen, deren systemati- 

 scher Bang lediglich dannch bestimmt wird, bis zu welchem Grade 



1) LoTSY, P. J. — l.c. 2) Engleb, A. — 1.c. p. IX. 3) Englkb, A. — l.c p. IX. 



