154 THE MINUTE ANATOMISTS 



vessels and rows of cells, and helped out with sup- 

 positions, whicli are altogether misleading. 



Bvds 



An interesting and useful object-lesson might be 

 founded upon Malpighi's explanations and figures. He 

 knows that the new buds become visible as soon as the 

 buds of the preceding year have expanded. He is quite 

 clear as to the nature of the bud ; it is an undeveloped 

 branch, a " compendium plantse." He gives a long 

 series of instructive figures to illustrate the development 

 of leaves and stipules. One misses a full account of the 

 bud-scales, and some discussion of their nature. 



Leaves 



Malpighi's account of the functions of leaves is un- 

 supported by a single experiment. He is guided by 

 analogy to the conclusion, that they are organs for the 

 elaboration and elimination of the crude sap, and are 

 analogous to the skin of an animal. The comparison 

 is, he thinks, borne out by the fall of the leaves, 

 when choked by waste products, which resembles the 

 periodical casting of an insect's skin.^ The sap, purified 

 in the leaves, supplies, he says, the young shoots and 

 buds. 



Malpighi's theory of plant nutrition may be summed 

 up thus : — Water and certain dissolved substances are 

 absorbed by the roots and ascend by the wood-fibres ; 

 these materials are elaborated in the leaves, superfluous 

 moisture being exhaled and waste matter eliminated ; 

 the elaborated sap passes down the stem by the vascular 

 bundles and may either supply new growths or be stored 



^Aristotle {De Oener. Anim., V. 3) had compared the fall of the leaf to the 

 fall of hairs, the moulting of feathers, &o. 



