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But, this can be accepted only in the case where one believes that species 
are formed only through the fixation of characters acquired by adaptation or 
direct influence, which characters are ever diverging. When we think of 
several othar causes of the formation of spacies, such as crossing and mutation, 
we can not but be forced to conclude that it is impossible to arrive at blood - 
affinity through indirect methods. The latter conclusion can be easily under- 
stood by one who accepts the participation theory. It is only in some special 
case thas we can see blood - relationship through the study of resemblanc2”. 
As blood - relationship is of course one of the natural relations manifested by 
organisms, it should certainly appzar in one phase of the dynamic system. 
But, it can not be definitely stated that blood - relationship is the only criterion 
for constituting a natural system. ENGLER goes on to say”: 
Es hat die Erfahrung gelehrt, daB auBerlich oft szhr dhnliche Organismen nur 
eine entfernte Verwandtschaft besitzen. 
This is indeed true. That is why I should say that a real natural relation 
is so and so in external form, but at the same time is manifested differently 
in blood - relationship. In this respact, his opinion differs from mine. Again 
he says” :— 
So ist man zu der Erkenntnis gelangt, da einzellige, kugelige, also Augerlich sehr 
Hhnliche Organismen nicht bloS sehr verschiedenen Familien, sondern auch verschie- 
denen Klassen und Abteilungen angehéren kénnen. 
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 special case where we know their blood - relationship exactly, it will 
be all right to arrange them according to this 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 difference in the criterion. The 
natural system should, therefore, be a dynamic one which manifests different 
phases when viewed from different standpoints. Further he proceeds to 
say: 
So gelangt man zur Feststellung von Verwandtschaftskreisen, deren systemati- 
scher Rang lediglich danach bestimmt wird, bis zu welchem Grade 
1) Lotsy, P. J.—le. 2) Evauer, A.—le. p. IX. 3) Eneter, A.—lec. p. IX. 
