264 THE VITAL FUNCTIONS. 



microscope, in the transparent membranes of 

 frogs or fishes. The splendid spectacle, thus 

 brought within the cognizance of our senses, of 

 unceasing activity in the minutest filaments of 

 the animal frame, and of the rapid transit of 

 streams of fluid, bearing along with them minute 

 particles, which appear to be pressing forwards, 

 like the passengers in the streets of a crowded 

 city, through multitudes of narrow and winding 

 passages, can never fail, when first beheld, to 

 fill the mind with astonishment * ; a feeling, 

 which must be exalted to the highest admiration 

 on reflecting that what we there behold is at all 

 times going on within us, during the whole 

 period of our lives, in every, even the minutest 

 portion of our frame. How inadequate, then, 

 must be any ideas we are capable of forming 

 of the incalculable number of movements and of 

 actions, which are conducted in the living sys- 

 tem ; and how infinite must be the prescience 

 and the wisdom, by which these multifarious and 

 complicated operations were so deeply planned, 

 and so harmoniously adjusted ! 



* Lewenhoeck, speaking of the delight he experienced on 

 viewing the circulation of the blood in tadpoles, uses the follow- 

 ing expressions. " This pleasure has oftentimes been so recrea- 

 ting to me, that I do not believe that all the pleasure of foun- 

 tains, or water-works, either natural or made by art, could have 

 pleased my sight so well, as the view of these creatures has 

 given jme." — Phil. Trans, xxii. 453. 



