256 PHILOSOPHICAL TRANSACTIONS. [aNNO 1675. 



he finds in the bark to be always and only sap vessels. In some, he finds sap- 

 vessels to be only lymphseducts ; in others, lymphasducts and lactiferous; in 

 others lymphaeducts and resiniferous ; lastly, in some, two kinds of lymphse- 

 ducts, and one of a sort of resinous. He also asserts the analogy between the 

 vessels of an animal and a plant. 3. Having described the bark, he proceeds 

 to the woody part ; and here in the several trunks he considers their two general 

 parts, namely, the parenchymous part or insertions, and the vessels; the ves- 

 sels have likewise much variety, yet are of two general kinds, namely, sap- ves- 

 sels and air-vessels, whereas it is proper to the bark to have only sap-vessels. 

 4. Lastly, he describes the pith; first in general, proving it to be, as to its 

 substance, the same with the parenchyma in the bark, and the insertions in the 

 wood ; stating its being compounded of two parts, a parenchyma and sap-ves- 

 sels; the parenchyma made up of bladders, of very different sizes and shapes 

 in different plants, and being of such a texture, that the sides of the greater 

 bladders are composed of lesser, in the same manner as the sap-vessels are, but 

 greater fibres made up of lesser. 



The second part of this book gives an account of the vegetation of trunks, 

 grounded on the foregoing anatomy, and showing the use that may be made of 

 the same, in order to explain the manner of vegetation : under the seven fol- 

 lowing heads: 



1. The motion and course of the sap. 2. The motion of the air; that it 

 first enters the plant by the trunk, but chiefly by the root, and is thence in a 

 peculiar manner distributed throughout the whole plant. 3. The structure of 

 the parts ; where he explains the unison of the bark to the body of the tree, 

 with the cause of it: considers the various surface and falling off" of the bark ; 

 the lessening of the pith in the elder-branches ; the ruptures of the pith, and 

 for what ends made; further, how the air-vessels come to be less in the trunk 

 of the same plant than in the root ; and those of the first year usually much 

 less than those of the years following ; as also, how the air-vessels come to be 

 formed always late in the year. 4. The generation of liquors, depending on the 

 structure and formation of the parts ; where he shows, that the concurrence of 

 two specifically distinct liquors is as necessary to nutrition in plants as in ani- 

 mals ; and that the vessels are the chief viscera of a plant ; the viscera of an 

 animal being but vessels conglomerated, and the vessels of a plant, only viscera 

 drawn out at length. To which he adds a particular explanation how a vinous 

 sap is made, how a resinous, oily and milky ; likewise, how the liquors of 

 plants come to be white ; what is a rosin properly so called ; what a gum ; what 

 a mucilage. 5. The figuration of trunks; where he renders the cause of a 

 shrub, a tall tree, a slender, and a thick tree, as also of the round or angular 



