Of Vegetation. 341 



llrong athletick conftitution ; for when grow- 

 ing Nature is deprived of proper materials for 

 this purpofe, then is me under a neceffity of 

 drawing out very flender threads of life, as is 

 too often the cafe of young growing perfons, 

 who, by indulging in fpirituous liquors, or 

 other excefles, do thereby greatly deprave the 

 nutritive ductile matter, whence all the dif- 

 tending fibres of the body are fupplied. 



Since we are by thefe Experiments afTured, 

 that the longitudinal fibres and fap-veflels of 

 wood in its firft year's growth, do thus diftend 

 in length by the extenfion of every part $ and 

 iince Nature in fimilar productions makes ufe 

 of the fame, or nearly the fame methods, thefe 

 confiderations make it not unreafonable to 

 think, that the fecond and following years 

 additional ringlets of v/ood are not formed 

 by a merely horizontal dilatation of the vef- 

 fels ; for it is not eafy to conceive, how lon- 

 gitudinal fibres and tubular fap-veffels mould 

 thus be formed, but rather by the fhooting 

 of the longitudinal tubes and fibres length- 

 ways from thofe of the lail year's wood, 

 whereby there is a free communication main- 

 tained between thefe and the fap-veffels of all 

 the preceding year's growth. The obferva- 

 tions on the manner of the growth of the 



Z 3 ringlets 



