86 INTRODUCTION. 



transmutation, or change from one being to another 

 Such an opinion presented no difficulties to those 

 who, like Virgil, imagined that a swarm of honey- 

 bees might be generated from a piece of putrid flesh ; 

 or, like Kircher, that a crop of serpents might he 

 reared from cut pieces of snakes, roasted, and sown 

 in an " oleaginous soil ;" and may even now seem 

 not untenable by such as believe that a horse-hair 

 placed in the water of a spring, will, in process of 

 time, be transformed into a hair-worm, or young 

 eel ! The accurate investigations of Malpighi and 

 Swammerdam were the first to show this subject in 

 its true light, by demonstrating in what the trans- 

 formations of butterflies essentially consist. By the 

 dissection of caterpillars an operation which they 

 performed with astonishing skill and delicacy they 

 were able to discover the parts of the future butter- 

 fly folded up within the body, in the same manner 

 as an embryo flower may be detected in the interior 

 of an unexpanded bud. " It is clearly and distinct- 

 ly seen," says Swammerdam, " that within the skin 

 of the caterpillar a perfect and real butterfly is hid- 

 den, and therefore the skin of the caterpillar must 

 be considered only as an outer garment, containing 

 in it parts belonging to the nature of a butterfly 

 which have grown under its defence by slow degrees, 

 in like manner as other sensitive bodies increase by 

 accretion." * In every caterpillar, therefore, there 

 exists, from the earliest period of its life, the germ 

 Book of Nature, ii. 26. 



