HISTORY OF PARTHENOGENESIS. 305 



In 184^2, the known facts were collected, and con- 

 nected under one generalisation by the Danish botanist 

 Steenstrup, who brought his own quota of important 

 facts. In this work, * a flash of light suddenly revealed 

 the connection in which many isolated paradoxes stood 

 to each other : a theory was proposed, which, although 

 really nothing but a metaphorical expression of the 

 already known facts, was very widely accepted as a 

 perfect solution of the difficulty. 



In 184?9, Professor Owen published his two lectures 

 on Parthenogenesis, in which, re-stating the results of 

 his investigations into the reproduction of Aphides 

 (18^3), he propounded a theory as a substitute for the 

 metaphor of Steenstrup, and one which uj) to this time 

 is the sole theory not open to the charge of being a 

 merely verbal explanation. In the same year, Yictor 

 Carus published a small work-f- containing some new 

 observations, and an ingenious classification. 



In 1851 Leuckart published an essay | to prove that 

 alternate generation was simply metamorphosis plus 



SlEBOLD, Ueher die Band-tind-Blasenwurmer, 1854, or in the larger woi'k 

 of KUCHEXMEISTER, Die in lend an dera Koiyer des lebenden Menschen 

 vorkomenenden Parasiien, 1855 ; a translation of which, by Dr Lankester, 

 has been published recently by the Sydenham Society. Van Beneden 

 has since published his splendid monograph Sur les Veis Intestinaux, 

 which gained the prize oflfered by the French Academy. 



* On the Alternation of Genei'ations. Translated for the Ray So- 

 ciety by Mr George Busk, 1846. 



-t* Zur nahern Kenntniss des Generationsivechsels, 1849. 



X SlEBOLD u Kolliker's Zeiischrift, iii. p. 170. He repeats the idea 

 in his work on Comparative Anatomy, written in conjunction with 

 Bergmann. [He has since published a valuable little work, Zur Kennt- 

 niss des Generatiomcwechsels, 1858.] 



U 



