OF NATURAL HISTORY. 293 



bufinefs of life, look forward to futurity, and have a defire of 

 marrying and of eftablifhing families. All the focial appe- 

 tites are in vigour ; folid and manly friendships are formed ; 

 and man goes on for fome time to enjoy every kind of happi- 

 nefs which his nature is capable of affording. I wifh the 

 next change had no exigence. At fifty or fixty, the mental 

 powers, in general, like thofe of the body, begin to decline, 

 till feeble and tremulous old age arrives, and death clofes the 

 mutable fcene of human life. 



With regard to quadrupeds^ both before and after birth, 

 they undergo fimilar, and many of them greater, changes of 

 form than thsfe of the human fpccies. Their mental pow- 

 ers, likewife, their difpoiitions and manners, as well as the 

 objects of their attention, vary according to the different 

 flages of their exiftence. Many of them come into the 

 world blind, and continue for fome time before they receive 

 the {qxi^q of feeing. How many changes are exhibited in 

 the dog from birth till all his members are completely form- 

 ed, and all his inftin^ls are unfolded and improved by expe- 

 rience and education ? The deer -kind acquire not their 

 magnificent and beautiful horns before the age of puberty ; 

 and even thefe are annually caft oiFand renewed. Similar 

 changes take place in quadrupeds of every denomination ; 

 with examples of which every man's experience and recol- 

 lection will readilv fupply him ; and, therefore, it is unnecef- 

 fary to be more particular. 



Neither are Birds , in their progrefs from birth to maturi- 

 ty, exempted from changes. Like quadrupeds, many birds 

 are blind for fome time after they are hatched. In this con- 

 dition, how different are their form and appearances from 

 thofe of the perfeft animals ! At firft, they are covered with 

 a kind of down inftead of feathers. Even after the feathers 

 ihoot, they are often of a colour different from that which 



they acquire when full grown. The beautifully variegated 



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