JO #y,THE mTBRlM OF PLANTS 



toroy,) and constantly added to by food as solid as the ^esk 

 it creates, and a& the blood it; j loducfs. There is no yearly 

 extension of body, except a trifling in(:rease at first, that 

 could require the absorption of such a fund of matter as tl)C 

 whole blood of the animal to produce it : but in a tree each 

 year creates almost a fifth qf jthe weight^.upless tj?B tree is 

 very large, in fruit, flowers, leaves, fresh branches, new rar 

 dicles, and seeds. Whence then could the returning jiiices 

 flow, exhausted as they must be? 1 haye weighed the yearly 

 increase in a small tree, and it far exceeded this calculation. 

 Besides in an animal the blood is form d in it, whereas in a 

 tree the sap is the juices of the earth. Nature would not 

 therefore draw up more than is necessary for its various pro- 

 ductione, merely to carry it down again. In animals the circu- 

 lation, increased by exercise, occasions a constant dissipatio,ii 

 of the several parts, which enter into its composition, and i^ 

 therefore, I understand, productive of a thousand goodcons^f 

 quences, without which the animal might become torpidapd 

 insensible, from the efle^ls produced on the brair) ; but in ^ 

 tree I see no end it can answer; nor cpuld I ever find any re- 

 turning vepsels that would carry coloured juices the contrary 

 way, though I have sought them in every part of the pl^nt, 

 As to the reason given, " that, if a deep piece of wood was 

 cut o^t,of a tree, a large portion of matter grew in the upper 

 - . part of the woupd, and none in tjie lower," it is easily to he 



ficcounted for. The momenta tree grows unhealthy, it gets 

 full of these bunches; but such a cut must at once produce 

 them. The ficst efifect of such a dilapidation is tq arrest thp 

 vigorous flow' of the sap: much of this is therefore stopped^ 

 and often breaks some of the wood vessels: this forms little 

 pools, which occasion the rot, while the other vessels, filled 

 >vith air, are inflated and increased: in the mean time the 

 line of life, which has been divided by the deep cut, shoots 

 put many new germes, and forms new wood to engender 

 jlhem ; and when you take off the lump so made, it is a mass 

 of loose wood, of rotten albumen, find new shoots half alive, 

 jmd half dead ; while the under part, losing its sap by ble^d- 

 jng, which the other could not do, as the vessels could not 

 discharge themselres backwards, ip only dried up; and the 

 {>W(}s, opt being able to form for want of the «ap, decay in the^r 



ftrst 



