FIRST LESSONS IN ZOOLOGY, 



INTRODUCTION. 



THE study of nature is the study of everything about 

 us which we can perceive by our senses. Every object 

 which we can see on the earth is either a mineral or a living 

 body. Mineral bodies are not only stones, crystals, or sand, 

 but they include the air, water, and gases. Minerals do 

 not live; they are lifeless bodies, while plants and animals 

 are living bodies. The study of natural history is the study 

 of minerals and rocks, of plants and animals; or, in other 

 words, of our earth and the minerals composing it, and of 

 the plants and animals which have either once lived or are 

 now living on its surface. 



Minerals sometimes appear to grow like plants, as in the 

 frost which forms the delicate leaf-like tracery on our win- 

 dows, and if we watch under a microscope the evaporation 

 of a few drops of salt water, we can see the solid particles 

 of salt in the water arrange themselves in delicate crystals, 

 which actually grow, becoming larger by adding particle 

 after particle to the outside. Thus small crystals may grow 

 and become large ones. We see, then, that growth in min- 

 erals consists in the addition of particle after particle of solid 

 matter to the outside of the growing body, 

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