158 ANIMAL INSTINCTS. 



detect the lines of separation. To the more doubtful 

 instances mentioned above we may add the sexual 

 instincts, those which express emotions of mind, as 

 laughter, weeping, sighing, "&c., and perhaps also cer- 

 tain infantile acts occurring at the very dawn of life. 

 But all these cases are less distinctly marked in their 

 nature and origin ; and looking at the instincts of man 

 and other animals collectively, we reach the general 

 conclusion that reason acting through the will, and 

 instinct guiding and governing the acts of life apart 

 from the will, exist in inverse ratio to each other 

 throughout the scale of the animal creation ; the latter 

 at a certain point encroaching so entirely upon the 

 former that life becomes a mere mechanism, however 

 complex and wonderful the functions performed. 



I say at a certain point ; but who can denote the 

 point at which every trace of intelligence is lost in the 

 blind compulsion of instinct? The little community 

 of sparrows in my London garden puts before me a 

 daily picture of the curious intermingling of the two 

 faculties ; and even in the nests of some birds we find 

 adaptations to altered physical conditions which in man 

 we should deem the result of intelligence. Experi- 

 ments show that even the rigid architecture of the bee- 

 hive and the equally rigid laws which govern this 

 insect community undergo changes, made by the bees 

 themselves, to remedy mischiefs inflicted from without. 

 Unless we can satisfy our reason, or rather shelter our 

 ignorance, by some such phrase as supplementary 

 instincts, we must needs admit that intelligence is at 

 work here. Many similar cases occur of contrivances 



