8o PERIOD III. 



scientific and practical interest have never ceased to 

 accumulate down to the present time. 



The Metamorphoses of Plants. 



Speculations concerning the nature of the flower 

 roused at one time an interest far beyond that felt in 

 most botanical questions. The literary eminence ot 

 Goethe, who took a leading" part in the discussion^ 

 heightened the excitement, and to this day often 

 prompts the inquiry : What does modern science think 

 of the Metamorphoses of Plants ? 



Let us first briefly notice some anticipations of 

 Goethe's famous essay. In the last years of the six- 

 teenth century Cesalpini, taking a hint from Aristotle,, 

 tried to establish a relation between certain parts of the 

 flower and the component layers of the stem. Linnaeiis 

 worked out the same notion more elaborately, and with 

 a confidence which sought little aid from evidence. His 

 wonderful theory of Prolepsis (Anticipation) need not be 

 described, far less discussed, here. He also borrowed 

 and adapted an analogy which had been thrown out by 

 Swammerdam. The bark of a tree, which according to 

 the theory of Prolepsis gives rise to the calyx of the 

 flower, he compared to the skin of a caterpillar, the 

 expansion of the calyx to the casting of the skin, and 

 the act of flowering to the metamorphosis by which the 

 caterpillar is converted into a moth or butterfly. More 

 rational than the speculations just cited, and more 

 suggestive to the morphologists of the future, are his 

 words : " Principium florum et foliorum idem est "" 

 (Flower and leaf have a common origin) — which was 

 not, however, a very novel remark in the eighteenth 

 century. Long before Linnaeus early botanists had 

 remarked the resemblance of sepals, petals, and seed- 



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