128 OF INSTINCT. SECT. XVI. 13. i. 



WhiHl: the wild tribes of birds choofe this time of the year 

 from their acquired knowledge, that the mild temperature of the 

 air is more convenient for hatching their eggs, and is foon likely 

 tofupply that kind of nourifhment,that is wanted for their young. 



If the genial warmth of the fpring produced the paifion of 

 love, as it expands the foliage of trees, all other animals mould 

 feel its influence as well as birds : bur, the viviparous creatures, 

 as they fuckle their young, that is, as they previously digeft the 

 natural food, that it may better fuit the tender ftomachs of their 

 offsping, experience the influence of this paflion at all -feafons 

 of the year, as cats and bitches. The graminivorous animals 

 indeed generally produce their young about the time when grafs 

 is fupplied in the greatefl plenty, but this is without any decree 

 of exatnefs, as appears from our cows, flieep and hares, and 

 may be a part of the traditional knowledge, which they learn 

 from the example of their parents. 



Their Contrafts of Marriage. 



Their mutual paflion, and the acquired knowledge, that their 

 joint labour is neceflary to procure fuftenance for their nume- 

 rous family, induces the wild birds to enter into a contract of 

 marriage, which does not however take place among the ducks, 

 geefe, and fowls, that are provided with their daily food from 

 our barns. 



An ingenious philofopher has lately denied that animals can 

 enter into contracts, and thinks this an eflential difference be- 

 tween them and the human creature : but does not daily ob- 

 fervation convince us, that they form contracts of friend fhip 

 with each other, and with mankind ? When puppies and kittens 

 play together, is there not a tacit contract, that they will not 

 hurt each other ? And does not your favourite dog expect you 

 ihould give him his daily food, for his fervices and attention to 

 you ? And thus barters his love for your protection ? In the 

 fame manner that all contracts are made amongii men, that do 

 not underftand each other's arbitary language. 



The ConftruSKon of their Nefts. 



i. They feem to be inftrufted how to build their nefts from 

 their obfervation of that, in which they were educated, and from 

 their knowledge of thofe things, that are molt agreeable to their 

 touch in refpect to warmth, cleanlinefs, and (lability. They 

 choofe their fituations from their ideas of fafety from their ene- 

 mies, and of fhelter from the weather. Nor is the colour of 



their 



