ORGANIZATION. 21 



15. LifCi All these peculiarities of organized, as contrasted with 

 inorganic bodies, will be seen to depend upon this : that the former 

 are living beings, or their products. The great characteristic of 

 plants and animals is life, which these beings enjoy, but minerals ' 

 do not. Of the essential nature of the vitality which so controls 

 the matter it becomes connected with, and of the nature of the 

 connection between the living principle and the organized structure, 

 we are wholly ignorant. We know nothing of Ufe except by the 

 phenomena it manifests in organized structures. We have adverted 

 only to some of the most universal of these phenomena, those which 

 are common to every kind of organized being. But these are so 

 essentially different from the manifestations of any known physical 

 force, that we are compelled to attribute them to a special principle. 

 We may safely infer, however, that life is not a product, or result, 

 of the organization; but is a force manifested in matter, winch it 

 controls and shapes into peculiar forms, — • into an apparatus, in 

 which means are manifestly adapted to ends, and by Which results 

 are attained that are in no other way attainable. As we rise in the 

 scale of organized structure from plants through the various grades 

 of the animal creation, the superadded vital manifestations become 

 more and more striking and peculiar. But the fundamental char- 

 acteristics of living beings, — those which all enjoy in common, and 

 which necessarily give rise to all the peculiai'ities above enumer- 

 ated (12), — are reducible to two, viz.: — 1. the power of self- 

 support, or assimilation, that of nourishing themselves by taking 

 in surrounding mineral matter and converting it into their own 

 proper substance ; by which individuals increase in bulk, or grow, 

 aiid maintain their life : 2. the power of self-division or reproduc- 

 tion, by which they increase in numbers and perpetuate the species.* 



16. Difference between Vegetables and Animals. The distinction be- 

 tween vegetables and minerals is therefore well defined. But the 

 line of demarcation between plants and animals is by no means 

 so readily drawn. Ordinarily, there can be no difficulty in dis- 

 tinguishing a vegetable from an animal. All the questionable 



* A single striking illustration may set both points in n strong light. The -; 

 larva of the flesh-fly possesses such power of assimilation, that it will increase 

 its own weight two hundred times in twenty-four hours ; and such consequent i 

 power of reproduction, that Linnajus perhaps did not exaggerate, when he 

 affirmed that " three flesh-flies would devour the carcass of a horse as quickly 

 as would a lion/' 



