30 PERIOD II. 



which closer scrutiny always brought to view still more 

 exquisite adaptations to the conditions of life. He was 

 able to throw a beam of steady light upon the per- 

 plexed question of insect-transformation, and swept 

 from his path the sophistries with which the philosophy 

 of the schools had obscured the change of the cater- 

 pillar into a moth, or of the tadpole into a frog. He 

 demonstrated the gradual progress of the apparently 

 sudden transformation of certain insects by dipping 

 into boiling water a full-fed caterpillar, and then ex- 

 posing the parts of the moth or butterfly, which had 

 almost attained their complete form beneath the larval 

 skin ; after this it was easy to discover the same parts 

 in the pupa. 



There is no more valuable chapter in Swammerdam's 

 great work, the Bihlia Naturce, or Book of Nature, 

 than that devoted to the hive-bee. This insect had 

 long been a favourite study, but only those who were 

 armed with a microscope and skilled in minute anatomy 

 could solve the many difficult questions with which it 

 was involved. Aristotle and other ancient naturalists 

 had spoken of the kiiig of the bees, which some bee- 

 masters of the seventeenth century had been inclined 

 to call the queen. Was 'it really true that the queen 

 was a female, perhaps the only female in the hive ? 

 This question Swammerdam decided by the clearest 

 anatomical proof — viz., by dissecting out her ovaries. 

 He pointed out the resemblances between the queen 

 and the workers, such as the possession of a sting by 

 both, but did not discover the reduced reproductive 

 organs of the workers, and wrongly declared that they 

 never lay eggs. He proved by elaborate dissections 

 that the drones are the males of the community. How 

 and when the queen is fertilised he could not make out. 



