REMARKS 



UPON A STATEMENT PUT FORTH BY PROFESSOR VALENTIN, 

 RESPECTING PREVIOUS RESEARCHES ON THE SUBJECT OF 

 THIS WORK. 



After I had finished this Treatise, I received the first part 

 of Wagner's 'Lehrbuch der Physiologic/ 1 Leipzig, 1839; 

 which was just then issuing from the press, and which con- 

 tained (at page 132) an outline of the development of the 

 animal tissues, communicated by Professor Valentin. The 

 author introduces the subject with some historical remarks, 

 in which he represents my researches as giving an essen- 

 tial completeness to the analogies between animal tissues 

 and vegetable cells which had been previously pointed out, 

 more particularly by himself. There are very many ways 

 of drawing a comparison between two objects, and simi- 

 litudes may be discovered which are opposed to the whole 

 internal construction of the things in which they are observed. 

 Everything, therefore, depends upon the sort of comparison 

 drawn. If Valentin's historical representation be justified, the 

 idea of a comparison, similar in its kind to that on which my 

 researches are based, must have a previous existence in his 

 earlier investigations. I have endeavoured to analyse the 

 fundamental idea of my investigation in the commencement 

 of the Third Section of this treatise ; it was this — that one 

 common principle of development forms the basis of all the 

 elementary particles of organisms. It originated in a com- 

 parison being drawn between a cartilage-cell and a vegetable 

 cell, in such sense, that the molecules are united together for 

 the formation of both of them, in accordance with similar laws, 

 since in both instances a nucleolus is first formed; around this 



1 Rudolph Wagner's Elements of Physiology, translated by R. Willis, m.h.. p. 214. 



