398 Food of Plants, 



common garden earth. Now, if these materials, that is to sa}', the manures, 

 were in the bottom of a bottle, and a sort of loose stopper put in the bottle, 

 such as a tuft of straw, and this manure occasionally well wetted with rain 

 water, and well warmed with summer heat, there would unquestionably be 

 formed a gas of some strength, and of such a penetrating kind, that if any 

 medium, such as a bit of sponge, a piece of porous brick or sandstone were 

 placed in its atmosphere, it would soon be charged with the gas in various 

 forms, as to fineness and intensity ; and, from what I have observed, it is in 

 this gaseous air that the vegetable extends, and where the gas is not there 

 the s|)ongioles extend not. For example, if you lay a turf on a border, you 

 will draw the roots near the top, or if you lay a stone or a tile, you will find 

 the roots right under it ; but \\ you loosen the soil in such a way that wind 

 can get in and gas out, you will look in vain for roots extending their feeders 

 into that medium. I am therefore strongly inclined to suspect that this is 

 the food of the tissue of which plants are built, and that the more of 

 this gas is secreted in the soil or media in which roots are placed, the 

 more quickly will they extend and multiply tissue : and such seems to be 

 the nature of the sap, that it is stored in small bags or bladders, and in 

 this form it lines and covers antl overlays all the more essential parts, in 

 the same way as the white of an egg surrounds the yolk, until like that it 

 becomes assimilated with the substance that it first fed and protected; and, as 

 if it required a separate chemical laboratory to complete its grand design, 

 as soon as it passes the collar of the stem, and visits upper air, it takes other 

 properties, as the tadpole takes to lungs and legs, and hops the meadow, that 

 erewhile was, like a fish, perfect to live and move in water. 



Thus the grubs and worms, that seem only slightly removed in the scale 

 of existence from the substance on which they feed, are only as it were pre- 

 pared victuals for a higher order of more perfect animals, such as birds, &c. 

 But what could be more to the purpose, in the present argument, than the 

 transformation of insects ? The gluttonous grub fattens upon rude simples, as 

 leaves and crude fare, yet secretes in this filthy carcass the materials of a 

 beautiful fly. Now, what nonsense would it not be, to say this fly is only a 

 modification of gooseberry leaves? for on that alone the grub fed from which 

 this grew. Hence I reason, that in plants there is certainly a great deal of 

 transformation in the secretions they store up : thus, the ball of a turnip is 

 a storehouse for the feeding of the flower stem ; therefore the highly elabo- 

 rated sap of the ball of the turnip changes its nature and consistency and 

 flows into the flower stem, leaving the ball a mere open sponge. Now this 

 ball of the turnip is an illustration, however clumsy, of the laws that I suspect 

 regulate the formation of the vegetable tissue. The little bladders full of 

 vegetable sap, pure white, are only, if I may use the expression, the atmo- 

 sphere or surrounding medium in which the more highly elaborated parts are 

 formed and fed, or, in other words, the grub of the future flower ; for 

 example, the well dug ground in summer, and well manured, must be more 

 or less impregnated with certain gases. In this medium the seed of a 

 plant is placed, and a change must take place ; for the dry and thirsty husk 

 of the seed, like the sponge in the bottle, gets a share of all the gases 

 that are in the earth and water around it, and begins to develope, swelling 

 its bags with sap more or less elaborated by its cotyledons ; and, having 

 the power, that is everywhere so evident in the works of the Creator, to 

 work out its own perfection, it first elaborates the gases around it into 

 bladders of sap seemingly tasteless, colourless, and so exceedingly deli- 

 cate that their formation under these circumstances seems a miracle. Into 

 these bladders the more elaborate parts of the plant penetrate and feed : thus 

 a growing tree, or a growing grain of mustard seed, must not, cannot, stand • 

 still. Like as in the beautiful frond-like appearances that are beheld on the glass 

 of a window on a frosty morning, or on a piece of water, the imperceptible 

 particles keep adding to the extremity of every branch, extending its sphere, 

 so it is with the spongioles or feeders of roots in a living growing plant. 



