60 NEHEMIAH GREW 



water, milk, oil, wine, ink, etc., or in any of these with solid 

 bodies, such as nitre and salt, dissolved in them. He points 

 out that the effect both on the plant and on the liquid should 

 be noted. The solid body should be weighed before solution, 

 and then, after the experiment is over, the liquid should be 

 evaporated and the solid again weighed. 



Another instance in which he suggested an experiment, 

 apparently without carrying it out, was in relation to the move- 

 ments of the stems of non-climbing plants. He seems to have 

 anticipated the nineteenth century discovery of nutation amongst 

 plants other than climbers, though he stopped short of actually 

 proving it. In his account of the Motions of Trunks he remarks, 

 " The Convolution of Plants, hath been observed only in those 

 that Climb. But it seems probable, that many others do 

 also wind\... Whether it be so, or not the Experiment may 

 easily be made by tying a Thred upon any of the Branches ; 

 setting down the respect it then hath to any Quarter in the 

 Heavens : for, if it shall appear in two or three Months, to have 

 changed its Situation towards some other Quarter ; it is certain 

 proof hereof." He noticed that some plants twine " by South 

 from East to West " and others " from West to East" and attri- 

 buted this to their being respectively under the influence of the 

 sun and the moon. 



Whenever Grew's notions of plant physiology depended 

 upon chemistry, they became, according to our modern ideas, 

 extremely difficult to follow. He held, among many other curious 

 beliefs, that salts obtained from any plant have a tendency to 

 crystallise out in a form resembling that plant, and adds, as 

 an illustration from the animal world, " though I have not seen 

 it my self, yet I have been told by one that doth not use to 

 phancy things, that the Volatile Salt of Vipers, will figure it self 

 into the semblance of little Vipers!' 



The mystical belief that characteristic " principles " permeate 

 all things, finds expression in his idea that the " frost flowers," 

 sometimes to be seen on a window pane, are evidence that the 

 air is impregnated with " Vegetable Principles!' Another fact, 

 which he brings forward in support of the same view, is that 

 the ground or water, when exposed for some time to air, 



