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FOUNDATIONS OF ANATOMY 35 



are formed with several orifices or passports, either for the 

 better avolation of superfluous sap, or for the admission 

 of aer." 



It is difficult to picture exactly what Grew thought was 

 the part played by the atmosphere in plant physiology ; 

 " that even a plant lives partly on aer, for the reception 

 whereof it hath those parts which are answerable to lungs " 

 would suggest at first that he was confusing photosynthesis 

 and respiration, but he goes on to tell us that this air is 

 absorbed by the roots and thence distributed by the vessels 

 and " insertions " to all parts of the plant's body. 



Fifty years previously the philosopher Jung had made 

 the unfortunate pronouncement " plant a est corpus vivens, 

 non sentiens," and Grew, like most of his successors indeed, 

 accepted the aphorism as true and thus tried to explain 

 the various movements of plant organs on purely physical 

 grounds. When he found himself unable to put forward a 

 mechanical explanation he solved the problem by referring 

 the movement to an " inherent tendency." He entirely 

 missed the conception of the plant as a sensitive organism 

 responding to stimuli, but that idea was one that could 

 not develop until the existence of protoplasm had been 

 recognised and its peculiar activities appreciated. 



Grew's conception of the more minute anatomy of 

 the plant will seem very strange to you. " The most 

 unfeigned and proper resemblance we can at present 

 make of the whole body of a plant, is, to a piece of fine 

 bone lace, when the women are working it upon the 

 cushion ; for the pith, insertions, and parenchyma of the 

 barque, are all extream fine and perfect lace work ; the 

 fibres of the pith running horizontally, as do the threds 

 in a piece of lace ; and bounding the several bladders of 

 the pith and barque, as the threds do the several holes 

 of the lace ; and making up the insertions without 

 bladders, or with very small ones, as the same threds 

 likewise do the close parts of the lace, which they call the 

 clothwork. And lastly, both the lignous and aer vessels, 



