AND ANIMAL LIFE. 99 



LXXXVI. In physics an effect is proportion- 

 ate to its cause, and the same holds good in the 

 animal frame in regard to all actions that are re- 

 ferrible to this department of science. If a ball 

 be thrown from the hand with great force, it will 

 overcome many obstacles which would retard the 

 course of another propelled with less energy ; but 

 suppose this ball to be thrown through a given 

 space where there are different objects presenting 

 different degrees of attraction or controlling powers, 

 and then we have an idea of the office of the 

 heart and the influence of certain organs in regu- 

 lating or restraining the diffusion of the sangui- 

 neous fluid. 



LXXXVIL Physiologists and Anatomists 

 have long been occupied with the minute struc- 

 ture of the heart and lungs, endeavouring to un- 

 fold their ultimate tissues, to describe the courses 

 or uses of vessels, or the number of nerves which 

 enter into their composition ; and these investi- 

 gations have been productive of many theories 

 and fanciful opinions, which, if true, would have 

 led to no application, but have given rise to one 

 consequence, which has perhaps tended more 

 than all others to mystify the operations of Na- 

 ture, I allude to the study of minute objects. 

 While the mind and the eye have been equally 

 on the stretch to understand and perceive the na- 

 ture of ultimate principles, they have almost en- 

 tirely forgot to observe and examine phenomena 



G2 



