OF FOREST-TREES. 



131 



than ordinary skill how to apply it : in order to which, the constitution cHAP. VI i. 

 and texture of plants and trees are philosophically to be considered ; ^^■^^V^-' 

 some affecting macerations with dung and other mixtures, (which I should 

 not much commend,) others quite the contrary, the quick and running 

 spring, dangerous enough, and worse than snow-water, which is not in 

 some cases to be rejected : generally, therefore, that were to be chosen, 



combinations of the nutritive particles, a number of different fluids are prepared in the 

 same plant. Matter is the same in all ; but the modification of it" makes things sweet or 

 sour, acid or mild. The universal juice of a plant is a limpid, subacid liquor, which flows 

 plentifully from a wound made in a tree v/hen the sap is rising. The Birch and the Vine 

 yield it in great abundance. This liquor, as it moves through the innumerable small 

 vessels, becomes more and more concocted, and is the general mass from which all the 

 juices are derived. It may be called the blood of the plant. By a certain modification, 

 it produces high-flavoured oils, gums, sugar, wax, turpentine, and even the constituent 

 parts of the plant itself. How this transmutation is performed, remains, and perhaps, ever 

 will remain, unknown. 



I hope it will not be objected to me, that in this examination I have been too minute. 



In the history of Nature we cannot be too particular. Every part of it demands our most 

 serious attention, and every part of it repays us for the labour w^ bestow. The wings of 

 the butterfly are painted by the same Almighty hand that made the sun. The meanest 

 vegetable, and the most finished animal, are equally the care of Providence. We constantly 

 view the wisdom of God in his works ; and yet, as the wise man observes, "hardly do we 

 guess aright at the things that are upon the earth, and with labour do we find the things 

 that are before us." 



3. GENERATION". It is well known that the ancients supposed two sorts of genera- 

 tion, to wit, equivocal and univocal. This latter, they said, took place when any thing was 

 produced from its proper egg or matrix ; the equivocal, when any living thing was 

 generated fortuitously or by chance, from the confused mixture of particles. Thus, e. g. 

 they believed that fleas were generated from urine and saw-dust ; that myriads of little 

 insects, like atoms, came up out of slimy water, and maggots out of cheese in the summer ; 

 that several sorts of herbs quickly sprang up out of mould taken from a considerable depth 

 below ground ; and lastly, that worms were produced from putrid carcasses. Others 

 thought that the Creator, at the beginning, mixed seeds and eggs with the earth every 

 where ; so that when such earth was dug up, and the sun, by his heat, had hatched the 

 seeds, they imagined that herbs, plants, and animals sprung up, which were concealed 

 therein from the creation. But all the ingenious men of this age, who have imbibed the 

 sound principles of natural philosophy and natural history, have long ago rejected this 

 ridiculous opinion. God at the first gave to every living thing its own proper seed, and 

 to each a tendency or propensity to propagate its species ; and established this first and 

 great law to remain unalterable, " Increase and multiply." If from putrefaction, and the 

 heat of the sun, living creatures and plants could be produced, it would have been need- 



