2 THE NATURE AND WOBK OF PLANTS 



plants also. Still further it would be found that 

 protoplasm has certain ways of doing things, certain 

 modes of action, or is governed by a number of laws, 

 no matter whether it is in the body of a plant or 

 animal. Very little is known of the composition of 

 protoplasm, except that a great many kinds of 

 material are used in its construction, and that these 

 materials are blended and woven together in a very 

 complex and intricate manner. Protoplasm is a very 

 delicate and sensitive substance, easily destroyed or 

 injured, hence when it forms the body of a phmt or 

 animal, it is generally necessary for it to construct 

 masses or sheets of lifeless substance, which it fash- 

 ions into tools for the performance of its work, or 

 into coverings which hide it from sight and protect 

 its fragile mechanism from damage by heat, cold, 

 dryness, or other agencies which might crush, tear, 

 or injure it in any manner. The yellowish masses 

 of slimy substance to be seen on decaying logs are 

 the bodies of a slime mould which is composed of 

 naked protoplasm. This organism is so low in the 

 scale of life that it is difficult to say whether it is 

 more like a plant or an animal, and it forms cover- 

 ings for its protoplasm in the reproductive stage 

 only. 



