THE STRUCTURE AND FUNCTION OF HIGHER PLANTS 69 



midst of manifold operations; every square foot of the walls is at work, 

 pulsing, circulating fluids, moving globes and disks about bewilderingly. 

 We feel the vibrations of .industry, as if we were in the midst of hard- 

 working machinery where all the noises have been muffled to a low roar. 

 Even the chamber is not mere space between the units of the factory. It 

 is full of activity. You can feel the currents of gas circulating — not in 

 happy-go-lucky drafts, but with orderly purpose. If you had only con- 

 sented to be made a thousand times smaller than your present lumbering 

 self of one three-thousandth of an inch, you could now see what is hap- 

 pening. As it is, there is no way to show you except by coloring the cur- 

 rents artificially. Hold your hands close over your eyes for a minute while 

 I release the necromantic dyes and let them diffuse themselves throughout 

 the room . . . No, not quite yet, another minute, please . . . Now you 

 may look. 



The red wisps that seep from the cells and come blowing out of the 

 passages between cells, making straight for the funnel above us and passing 

 to the outer air, are oxygen. The bits of gray haze, which float gently from 

 the cells toward the funnel and disappear upward through it, are water- 

 vapor. The dark-green strands which steal in toward us from the breathing- 

 hole, drifting toward the cells and disappearing into them, are carbon 

 dioxide. As we watch these currents they seem gentle and aimless; there 

 is nothing exciting in their appearance. But if we had super-eyes which 

 could penetrate to all that is taking place, we should know that we are ob- 

 serving the most fundamental mystery in all the course of nature. We are 

 seeing the inorganic world made organic. Be polite for the space of a para- 

 graph while I tell what this means. 



A leaf — whether of palm or geranium or cactus or pine — is a factory for 

 converting water and carbon dioxide into organic food. Nowhere else in 

 nature can this miracle be performed. Each of the cells that surround us is 

 an organism which receives a supply of water from the ground and a 

 supply of carbon dioxide from a breathing-hole. Its energy is supplied by 

 the sunlight, from which it extracts certain rays and apphes them to the 

 water and the gas. By a process too elaborate and profound for the in- 

 vestigation of chemists it turns the energy of light waves upon these simple 

 molecules, mingling six of each in a massive and unstable molecule of 

 grape sugar — CeHjaOg. This is easily and quickly converted to starch; it 

 is altered to protein by the addition of elements brought from the ground; 

 it is the basis of all animal hfe — for no animal could exist but for the food 

 that is manufactured in leaves. The animal kingdom is a parasite upon the 

 industry of the sugar-making disks. 



If the cell were a perfectly efficient laboratory, it would build sugar 

 molecules without wasting any water. For water is precious; it must be 

 pursued by millions of industrious rootlets that fight their way through 

 harsh masses of dry soil to wring from it the moisture that it grudges to 



