METAMORPHOSES. 77 



scarcely ever more than a very small quantity ; for the reception of which 

 its stomach has been contracted, in some instances, to a tenth of its for- 

 mer bulk. Its almost sole object is now the multiplication of its kind, from 

 which it is diverted by no other propensity; and this important duty being 

 performed, the end of its existence has been answered, and it expires. 



It must be confessed that some objections might be 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 

 conclude 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 silkworm ! 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 silkworm 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. 



7* 



