THE STRUCTURE AND FUNCTION OF HIGHER PLANTS 73 



angles, that would withstand any storm, though carrying a load of sails, 

 and never be twisted or snapped in two. Human engineers will 

 never devise the struts for such a truss. We marvel when we are small- 

 sized tourists, but we never give a branch a moment's thought when we 

 are sixty-nine inches tall. 



If we should stop off midway of the branch, and if we had axes, and if 

 we had enough time and a supply of food, we might cut our way out of 

 this sap tunnel and hack a passage to the spongy heart of the branch. There 

 we should find some open spaces. We could walk all the way to the trunk 

 of the tree. But in order to reach such a passage we should have to chop for 

 nearly a mile. I suppose you would prefer to ride. You may as well go to 

 sleep, for we can hardly reach our destination in less than thirty hours. 



When I think of the trunk of this tree, and of how my dull mind has 

 never heeded it, I know that the soul of a savage is more sensitive than mine. 

 It understands better than my cast-iron brain what a tree is. The savage 

 discerns a spirit in it, he worships. I have never thought of anything in it 

 but a wood-pile. The savage perceives a kind of truth that is hidden from 

 all us bridge-playing joy-riders. Even a "vitalist" mystic has had more per- 

 ception than I. Henceforth I shall try to lift up my eyes to the structures 

 not made with hands. I shall never be able to see the spirit, nor can I ever 

 credit the "vital principle"; for to my prejudiced intellect these seem 

 fancies. But I can at least contemplate the unknown god of cytology and 

 learn to have a humble mind when I see a spire of marvels spreading its 

 magical green shops to the sun. 



This trunk bears its leaves to a height of four thousand miles above the 

 earth and spreads them two thousand miles on every side. In its construc- 

 tion there were no cables or cement or steel girders; there were no materials 

 but soft, living cells that formed six-inch walls and pieced the walls to- 

 gether. Out of these tubular sections, whose average length is not more than 

 fifty feet, they devise continuous pipe lines from the most remote root-tip 

 to the highest and farthest needle — ten thousand miles. 



On down the trunk we glide. We reach the level of the ground. We 

 continue down for more than a hundred miles, and then can feel that our 

 course is nearly horizontal. Our surroundings are cooler, for we are in a 

 root, traveling out toward a big branch of it. 



The current has almost ceased to flow. It is constricted in a narrower 

 passage, and its load of foods is being doled out to hungry cells whose 

 energy must be restored. Have no fear of them. They know what food they 

 need and will not nibble at us. Be alert and don't let yourself get stranded 

 in the smaller and more closely packed cells that now surround us. Keep 

 edging your way along with all your might. 



This rootlet is one hundred fifty yards thick at the point where we are, 

 five hundred yards from the very tip. We must force our passage amidst 

 these small, vigorous young cells that crowd before us so stoutly. It is hard 



