Science |Jn»gre$s. 



No. 2. April, 1894. Vol. I. 



EPIGENESIS OR EVOLUTION. 



DES Sages appeles a eclairer la Monde ont choque 

 les regies de la logique la plus commune. lis 

 ont juge du terns ou les parties d'un animal ont commence 

 d'exister par celui ou elles sont commence a devenir visibles ; 

 et tout ce qu'ils ne voyaient point, n'existoit point." 



These words, written by Bonnet nearly a century and 

 a quarter ago, are expressive of the belief in the evolu- 

 tionary theory of development, then universally accepted 

 in spite of the labours of Harvey and C. F. Wolff. This 

 evolutionary doctrine, after being thoroughly discredited by 

 the labours of the embryologists of the last fifty years, is now 

 with us again, not perhaps in its old form, the evolutionists 

 of to-day are anxious to repudiate that, but in a form which 

 differs from the old one only because of the more numerous 

 accumulation of facts and observed sequences which the 

 theory is called upon to explain. 



The evolution doctrine in its earliest phases was crude 

 enough : An animal was supposed to pre-exist fully formed 

 and complete within the egg, but as a miniature, generally 

 so small as to be unrecognisable by the eye, even when 

 aided by the best optical instruments then in use. This 

 somewhat singular view was founded chiefly on a supposed 

 observation of Malpighi, who had affirmed that he had seen 

 the body of the chick in the egg at the time at which it 



was laid and before it had been incubated. The observa- 



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