APPENDIX. 113 



furnish food for the summer, as some industrious 

 animals will do to nourish themselves in the win- 

 ter. In the next place, it may not be amiss to 

 confute a common opinion, That the sap returns 

 to the root in winter; for if it did so, how comes 

 it that trees which are cut down in November 

 and December will put forth branches and leaves 

 the following spring, although they have no root 

 or earth to feed them? This plainly shows that 

 the sap is condensed or thickened in the tree du- 

 ring its circulative course by extreme cold, and 

 remains in that gummy state till the warmth of 

 the spring (as I have already said) liquefies it, and 

 by the vapour which must then arise from it the 

 buds are pushed forth, so long as there is matter 

 remaining in the trunk sufficient to furnish them. 



" And now since it appears from what has been 

 said that plants have a circulation of sap, and 

 proper means whereby to supply themselves with 

 food, let us consider whether plants in their se- 

 veral kinds do not require different sorts of food 

 one from the other, like various sorts of animals 

 which differ in their diets. First, then, land ani- 

 mals may be likened in general to those plants 



