574 THE PLANT’S PLACE IN NATURE 
on the other hand, is generally solid and so requires to be dis- 
solved in a digestive cavity within the body before absorp- 
tion is possible. Plants which can make their own food from — 
materials always at hand have no such need for traveling 
about in search of food as most animals have; and while 
food-seeking calls for the special sensitiveness which Linnzeus 
termed feeling, food-making involves only such manifesta- 
tions of irritability as might easily escape his notice. A 
typical plant is thus a sedentary food-maker, a typical 
animal being a roving eater. It is only when plants lose 
more or less their power of making food, and animals their 
power of locomotion that doubt arises as to their kingdom, 
and then the question has to be decided not so much by 
rules and definitions, as by evidences of their kinship to un- 
doubted examples of vegetable or animal life. 
A Bacterium, for example, is classed as a plant because of re- 
semblances to a Nostoce which outweigh its animal-like motility and 
dependence upon organic food. If a Bacterium should develop a 
digestive cavity for the reception of its food we should say it had 
become an animal. 
The most fundamental difference between plants and 
animals appears thus to lie in the ways they prefer to get their 
food—the vegetable way being to make the best of what 
comes to it, the animal choosing rather to capture what 
plants have made. Returning to our simile of the boats it 
might be said that the vegetable craft choose to anchor in a 
stream of materials which they organize into food, while 
the animal craft navigate the stream and repair their losses 
entirely from other vessels. A modern revision of the aph- 
orism of Linneus, still, however, confessedly inaccurate, 
might read:—minerals crystallize; plants organize or re- 
organize materials which they absorb; animals reorganize 
food which they have swallowed. 
200. Plants in general. The foregoing reflections upon 
the way natural objects are related to one another are in- 
tended especially to emphasize the pivotal place which plants 
hold in the economy of nature. It is now believed that the 
wide and rich possibilities of earthly life could not have 
been gained or maintained without plants. Plants were 
