CHAP, i.] Theory of Evolution and Epigcncsis. 403 



tion of plants, Wolff says: 'Ordinarily plants are produced 

 from seeds, for the seed not only contains the plant in embryo 

 but also its first food.' He says that propagation by means of 

 buds is equally natural, for each bud contains a branch in little. 

 ' \Ve find inside in the flower a number of stalks disposed in a 

 circle, and something at the top of each, which is full of dust 

 and lets the dust fall on the tipper part of that which holds the 

 seed ; this organ is compared by some to the genitals of the 

 animal, and the dust to the male seed ; they think also that the 

 seed is made fruitful by the dust, and that therefore the embryo 

 must be conveyed by the dust into the seed-case and there be 

 formed into seeds. I have proposed to examine into the 

 matter, but I have always let it escape me.' . . . 'Since all 

 that has been hitherto adduced is found also in flowers which 

 spring from bulbs, and it is also certain that the leaves of bulbs 

 have consequently embryos in them ... it is easy to see that 

 the embryos must come from the leaves of the bulbs. And 

 since they could as easily be conveyed from there into the 

 seed-grains with the sap, as into the dust which is produced in 

 the upper part of the flower, I am inclined to think that this 

 is the true account of the matter and that it will be confirmed 

 by experience. But now comes the main question, whence 

 come the embryos into the sap ; since they have not an 

 external figure only but an internal structure also, it is not 

 plain how they can be formed either by the mere inner move- 

 ment of the sap, or by separation of certain parts. . . . And this 

 is certainly more credible, that the embryos already exist in 

 little in the sap and the plant, before they are brought by some 

 change into the condition in which they are met with in the 

 seed and in buds. l!ut there is the further question where 

 they were previously. They must either lie one in another in a 

 minute form, as Malebranche especially maintains, or they arc- 

 brought from the air and the earth with the nourishing sap 

 into the plant, an idea which Honoratus Fabri Advanced and 

 Perrault and Sturm developed after him. According to the 

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