462 Transactions of the American Institute. 



and how tliey build up the parent stem and aid in unfolding' the 

 buds and in developing the leaves and fruits, constitute one of the 

 most useful and important branches of practical agriculture. The 

 tiller of the soil who does not understand something of the office of 

 roots 7nay, by accident succeed. A correct understanding of the 

 functions of growing plants and their roots is fundamental to a mas- 

 tery of the principles upon which sound agriculture depends. Roots 

 are things of life. Yegetable life is as real and important as animal 

 life ; and the little white rootlets, no bigger than a knitting needle, 

 that push their obscure way through the dim and turbid soil, are as 

 much alive as earth worms or grubs, or the insects that burrow under 

 the sod. The philosophy of vegetable economy in the soil ismysteri- 

 oxis. It cannot be studied, because when we invade those dim and 

 silent kingdoms with the scrutiny of our science, this very intrusion 

 arrests the living process we would study. When a certain amount 

 of moisture and heat have entered the seed, the germ, quickened into 

 life, pushes out a root, which always precedes the stem. As soon as 

 the radicle has burst through the integument of the kernel the tender 

 extremity is provided with a portion of a radicle of a soft texture, 

 which the botanists call a spongiole or little sponge, because its chief 

 duty is to absorb water that has been enriched by taking into solu- 

 tion portions of plant food. These little roots are provided with a 

 cap or tip much harder than the body of the spongiole, somewhat as 

 the feet of the- mole or woodchuck are armed with nails. This cap is 

 perforated with numerous small holes, large enough to admit such 

 liquid as the spongiole might require to lengthen the root by adding 

 particle to atom behind this shield as the elongation of each root is 

 affected. This cap on the extremity of the root maj?- also be com- 

 pared to a mole-plow, which is thrust forward through the seed-lid as 

 fast as material is accumulated to construct the body of the root, just 

 as a mason forms a culvert or cement water pipe by building on 

 brick after brick, or by continuing to a]>ply more and more 

 mortar at one end of his work. Here, at the extremity of the root, 

 is where its growth, lengthways, takes place. And here also, behind 

 this indurated cap is the stomach, so to speak, of the root. Tiie 

 pabulum is received into the spongiole, digested, to all intents and 

 purposes, just as much as the food that enters the stomach of a living 

 animal. Here it is concocted into sap and fibrous material; and by 

 a process which mortals are not permitted to look into ; as all this 

 occurs in darkness, the hard cap, or point of the miniature mole 



