120 RAY AND SOME OF HIS FELLOW-WORKERS 



They studied the bleeding of fresh- cut truncheons of 

 birch and sycamore, and also of roots of the same trees. , 

 When the truncheon was held vertically, it might be fl 

 made to bleed at either end. Water supplied by means ^ 

 of a cell of wax to the upper end of a truncheon of birch 

 could be made to run out at the lower end, and this 

 happened whether the truncheon was held in its natural 

 position or inverted. The temperatures are only casually 

 mentioned, and the same work had afterwards to be 

 repeated with greater exactness. They showed that 

 " sap " exudes, not only between the bark and the 

 wood, and from the " pricked circles " [of dotted ducts] 

 " between the coats of the wood," but also from the 

 "very body of the wood." They also investigated the 

 flow from holes bored in a birch and a sycamore. 



Many years later Eay, in his Wisdom of God mani- 

 fested in the works of the Creation (1691), adds this 

 interesting note : — " That there is a regress of the 

 Sap in Plants from above downwards, and that this 

 descendent Juice is that which principally nourisheth 

 both Fruit and Plant, is clearly proved by the experi- 

 ments of Seignor Malpighii, and those of an ingenious 

 Country-Man of our own, Thomas Broth erton. Esquire,^ 

 of which I shall mention only one, that is, if you cut 

 off a ring of Bark from the Trunk of any tree, that Part 

 of the Tree above the Barked King shall grow and 

 increase in Bigness, but not that beneath." The reader 

 who turns to Malpighi's Anatome Plantarum in order 

 to see what the experiments were by which he established 

 the existence of a descent of the sap, will be disap- 

 pointed ; it was not by experiments but by arguments 

 that Malpighi reached his conclusion.^ 



^ Phil. Trans. No. 187. ^ Anat. PlaiUarmn, pp. 38-9. 



