THE THEORIA GENERATIONIS. 27 1 



considerable size. And here the theorist triumphed over the 

 empirical observer, for he could assert, what was not easily- 

 disproved, that owing to their transparency the microscope 

 must ever fail to reveal the germs incased one within the 

 other. 



The Siegfried destined to overcome this monstrous theory of 

 emboitenient, a theory not only false in itself, but one jealously 

 guarding the problem of development, and preventing all access 

 to it, as the dragon guarded the treasure of the Niebelungen, 

 was Caspar FriedricJi Wolff. Wolff, one of the many great 

 intellects that northern Germany has produced, was born in 

 Berlin in 1733. You will find nearly all that is known of his 

 life in a letter by his amanuensis Mursinna to Goethe, pub- 

 lished by the great German poet in his MorpJioIogie} The 

 scant facts of this letter, with Wolff's own writings, in which 

 his personality is studiously kept in reserve after the manner 

 of scientific men, leaves us with a sense of uncertainty not 

 entirely free from sadness. We long to know more of this 

 sweet-natured student who, at the early age of six-and-twenty, 

 was an intellectual giant, defending an epoch-making thesis, the 

 theoria generationis, simply pro gradit doctoris medicinae. 



Before giving a brief account of this Theoria it may be 

 well to try to form some idea of its author's general mental 

 characteristics. Wolff was a disciple of Aristotle. The training 

 of the schoolman is only too apparent in all his scientific writ- 

 ings, apart from Mursinna's statement ^ to the effect that when 

 Wolff was lecturing on medicine in Berlin " he taught logic prob- 

 ably better than it had ever been taught before, and applied it 

 in particular to medicine, thereby creating, so to speak, a new 

 spirit in his hearers, so that they were enabled to understand 

 and assimilate his other teachings more easily." His skill in 

 deductive logic seems to have been noticed by Sachs, ^ who 

 claims that some of Wolff's observations on plant structure 

 " are highly inexact, and influenced by preconceived opinions, 

 and his account of them is rendered obscure and often quite 



1 Goethe. Morphologie, 1820, pp. 252-256. 



2 Goethe. Morphologie, p. 254. 



3 Sachs. History of Botany, p. 251. 



