HISTORICAL OR COMPARATIVE METHOD 61 



Lyonet, that though viviparous reproduction without 

 males went on regularly so long- as food was plentiful, 

 males appeared towards the end of summer, and 

 fertilised the eggs which were destined to outlast the 

 winter. 



The aphids added a new and peculiar example to the 

 known cases of asexual propagation (plants and Hydra). 

 Much discussion followed, but the physiology of that 

 age (and the same is true .of the physiology of our own 

 age) was unable to reveal the full significance of the 

 observed facts. Insects have since furnished many 

 instances of unfertilised eggs which yield offspring. 

 One such instance was already recorded, though neither 

 Leeuwenhoek, Reaumur, nor Bonnet knew of it. In 

 the year 1701 Albrecht of Hildesheim placed a pupa 

 in a glass vessel and forgot it. A moth hatched out 

 and laid eggs, from which a number of caterpillars 

 issued. 



Lyonet, whom we have more than once had occasion 

 to mention, afterwards became celebrated as the author 

 of one of the most laborious and beautiful of insect- 

 monographs. The structure of the larva of the goat- 

 moth was depicted by him in eighteen quarto plates, 

 crowded with detail. 



The Historical or Comparative Method: Montesquieu 

 and Buffon. 



About the middle of the eighteenth century we remark 

 the introduction of a new, or almost new, method of 

 investigation, which was destined to achieve great 

 results. Hitherto many men had been sanguine enough 

 to believe that they could think out or decide by argu- 

 ment hard questions respecting the origin of what they 

 saw about them. It was easier, but not really more 



