METAMORPHOSES. 79 



thrown out against this hypothesis, yet I think none that 

 would not admit of a plausible answer. To these it is 

 foreign to my purpose now to attend, and I shall con- 

 clude this letter by pointing out to you the variety of 

 new relations which this arrangement introduces into 

 nature. One individual unites in itself, in fact, three 

 species, whose modes of existence are often as different 

 as those of the most distantly related animals of other 

 tribes. The same insect often lives successively in three 

 or four worlds. It is an inhabitant of the water during 

 one period ; of the earth during another ; and of the air 

 during a third ; and fitted for its various abodes by new 

 organs and instruments, and a new form in each. Think 

 (to use an illustration of Bonnet) but of the cocoon of 

 the silk-worm ! How many hands, how many machines 

 does not this little ball put into motion ! Of what riches 

 should we not have been deprived, if the moth of the 

 silk-worm had been born a moth, without having been 

 previously a caterpillar ! The domestic economy of a large 

 portion of mankind would have been formed on a plan 

 altogether different from that which now prevails. 



I am, &c. 



