CHAP, ii.] of Plants. Cesalpino. 45 1 



experience at his disposition than his master, and it is instruc- 

 tive therefore to make a nearer acquaintance with his views, 

 because they show how far the old philosophy was in a con- 

 dition to turn better empirical knowledge than Aristotle 

 possessed to a satisfactory use ; they will also show that 

 Cesalpino's first essays led him to views which can no longer 

 be said to be strictly Aristotelian. 



In the second chapter of the first book of the work from which 

 we have already quoted, 'De plantis libri XVI,' 1583, he raises the 

 question, in what way the food of plants is taken in and their 

 nutrition accomplished. In animals we see the food conveyed 

 from the veins to the heart, which is the laboratory of the warmth 

 of the body, and after it has been finally perfected there, 

 spread abroad through the arteries into all parts of the 

 body ; and this is effected by the operation of the force 

 (spiritus) which is generated in the heart from the food. In 

 plants on the contrary we see no veins, or other channels, nor 

 do we feel any warmth in them, so that it is difficult to under- 

 stand how trees grow to so great a size, since they seem to 

 have much less natural heat than animals. Cesalpino explains 

 this enigma by saying, that animals require much food for 

 maintaining the activity of the senses and the movements of 

 their organs. The larger quantity of animal food also requires 

 larger receptacles, namely the veins. Plants on the other 

 hand need less food, because this is only used for purposes of 

 nutrition, or to a very small extent for the production of 

 internal heat as well, and therefore they grow more vigorously 

 and bear more fruit than animals. At the same time plants 

 are not without internal heat, though it cannot be perceived 

 by the touch because all objects seem cold to us, which are 

 less warm than our organ of feeling. That plants moreover 

 have veins, though only narrow ones in accordance with the 

 small mass of their food, is shown by those which yield a 

 milky juice, such as Euphorbia and Ficus, which when cut 

 bleed like the flesh of animals ; Cesalpino adds * and this is 



Gg 2 



