GENERAL CHARACTERS OP LIVING BEINGS. 17 



which is called muscle ; the property, namely, of contracting, 

 when a stimulus or irritation is applied to it. This and many 

 other properties, therefore, which are exhibited by organised 

 stfuctures, and to which we see nothing analogous in inorganic 

 matter, are termed vital; and it is by the operation of these 

 properties, that the series of changes is produced, which consti- 

 tutes the Life of any organised being, whether Plant or Animal. 

 Thus the heart has the property of contractility, which, when 

 exercised, causes its contraction ; the eye has the property of 

 receiving the impressions of light, which, when exercised, causes 

 sensation ; and so on. 



5. It may be asked, whence do these peculiar properties 

 arise ? Are living bodies composed of different elements from 

 those which exist around us in the form of dead matter ? Or are 

 the elements the same, in a different state of combination ? And 

 can we attribute the peculiar properties of organised tissues to 

 the peculiar state in which their particles exist ? 



6. To this it may be replied, that there is no element entering 

 into the composition of organised bodies, which is not also found 

 in the world around ; and further, that their chief elements are 

 very few in number, compared with those which we find else- 

 where. But the state of combination in which they exist is 

 altogether peculiar, and such as the chemist cannot imitate ; any 

 more than the mechanic can imitate the arrangement of their 

 particles. In fact, every organised structure with which we are 

 acquainted, had its origin in another, which produced a germ 

 capable of living and growing, and of constructing its peculiar 

 fabric out of the materials it derives from the inorganic world ; 

 and this again was produced by a former one; and so on. 



7. We perceive, therefore, that as the living organised 

 beings which we now witness around us, are all the descendants 

 of others, whose succession we might trace backwards to their 

 first parentage, their actions are as much the results of the 

 general laws which the Creator of all impressed on the frame of 

 His first-formed creatures, as are the movements of the planets 

 round the sun, of the laws which He impressed on them, when 

 He first set those glorious spheres in motion. These laws are 



