92 SCIENCE PRIMERS. [IMMATERIAL 



mineral matter and living matter. The elements of 

 living matter are identical with those of mineral 

 bodies ; and the fundamental laws of matter and 

 motion apply as much to living matter as to mineral 

 matter ; but every living body is, as it were, a com- 

 plicated piece of mechanism which " goes," or lives, 

 only under certain conditions. The germ contained 

 in the fowl's egg requires nothing but a supply of 

 warmth, within certain narrow limits of temperature, 

 to build the molecules of the egg into the body of 

 the chick. And the process of development of the 

 egg, like that of the seed, is neither more nor less 

 mysterious than that, in virtue of which, the mole- 

 cules of water, when it is cooled down to the freezing- 

 point, build themselves up into regular crystals. 



The further study of living bodies leads to the 

 province of Biology, of which there are two great 

 divisions Botany, which deals with plants, and 

 Zoology, which treats of animals. 



Each of these divisions has its subdivisions such 

 as Morphology, which treats of the form, structure, 

 and development of living beings, and Physiology, 

 which explains their actions or functions, besides 

 others. 



III. IMMATERIAL OBJECTS. 



66. Mental Phenomena. 



Material objects are all either not living, that is to 

 say, mineral bodies, or they are living bodies. Every- 

 thing which occupies space, offers resistance, has 

 weight, and transfers motion, belongs to one or 



