SERIES OF VITAL FUNCTIONS. 69 



the cuttle-fish screens itself from pursuit by effu- 

 sing an intensely dark coloured ink, which renders 

 the surrounding waters so black and turbid as to 

 conceal the animal, and favour its escape ; the 

 torpedo defends itself from molestation by reite- 

 rated discharges from its electric battery ; the 

 butterfly avoids capture by its irregular move- 

 ments in the air, and the hare puts the hounds 

 at fault by her mazy doublings. Thus does 

 the animated creation present a busy scene 

 of activity and employment : thus are a variety 

 of powers called forth, and an infinite diversity 

 of pleasures derived from their exercise ; and 

 existence is on the whole rendered the source of 

 incomparably higher degrees, as well as of a larger 

 amount of enjoyment, than appears to have been 

 compatible with any other imaginable system. 



§ 2. Series of Vital Functions. 



In the animal economy, as in the vegetable, the 

 vital, or nutritive functions are divisible into seven 

 kinds, namely, Assimilation, Circulation, Respi- 

 ration, Secretion, Excretion, Absorption, and 

 Nutrition ; some of which even admit of further 

 subdivision. This is the case more particularly 

 with the processes of assimilation, which are 

 generally numerous, and require a very compli- 

 cated apparatus for acting on the food in all the 



