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Thus I object prima facie to a demonstration, for it can lead to 
no useful result. 
If the facts Ihave described were easily verified or easily observed, 
there would have been no need for Ragı or I to have talked of the 
matter at all; the development of the peripheral nervous system would 
have been solved, and settled for ever years ago. But, on the au- 
thority of one of Ragr's friends, Prof. O. Hertwia, this question 
is one of the most difficult in the domain of embryology: and it is 
this difficult point which Prof. RABL proposes to leave to the hasty 
decision of a body of morphologists, most of whom have no acquaint- 
ance with nerve or ganglion development! 
It would be interesting to know why Prof. RagL has not proposed 
the same mode of settling other differences as to matters of fact; such 
as the contradictions between his theories and supposed facts on the 
one hand and the facts of development as recorded by such embryolo- 
gists as Profs. KLEINENBERG, KÖLLIKER and Dr. SARASIN, to name 
only these of the great number whose facts are opposed to RABL’s 
theories. 
I cannot help admiring the apparent ingenuousness of Prof. RABL’s 
invitation, for surely Rast knows as well as I do that from a superficial 
examination of preparations, such as he proposes, anyone would almost 
certainly attain the conviction that RABL was advocate for the side 
of truth, while I was supporting obvious falsehoods! 
RABL judges my attitude of thought from his own: he is so much 
impressed & priori with Amphioxus, that he sets to work to reduce 
the Ichthyopsida etc. to the Amphioxus developmental scheme. 
He insinuates that my observations were undertaken to make the 
Vertebrate nervous system fit in nolens volens with that of the Anne- 
lid. That is a mistake: I have openly declared the influence of KLEI- 
NENBERG’S work in impelling my researches, but not in modelling the 
results to be attained. KLEINENBERG had shown how complicated was 
the manner in which the Annelid nervous system arose, and the na- 
tural thought to any embryologist who believed in the truth, sincerity 
and extreme importance of KLEINENBERG’S statements as I did, would 
be to look whether any such complicated modus operandi were at the 
bottom of the ontogenetic evolution of the even more complex nervous 
system of the Vertebrata. 
That KLEINENBERG’S suspicions of similar complications in the 
latter case were justifiable, and that my desire to make further re- 
searches was borne out by the results is proved by my discovery of a 
