CH. xxxvin. CONRAD SP REN GEL. 415 



green leaf-like blossoms to the most gorgeous colours. The 

 green leaves called sepals, which lie under the yellow petals 

 in the buttercup, are transformed into brilliantly coloured 

 petals in the tulip, while in some cases, such as occasionally 

 in white clover, the whole flower, sepals, petals, pistil and 

 stamens, has been known to be changed into little leaflets 

 growing as if upon a branch. 



For this reason gardeners find it possible to cultivate a 

 plant so that it shall be all leaves and no flower, or, on the 

 other hand, shall have a gorgeous flower while the leaves 

 remain small and insignificant And thus we are led to see 

 that all the different parts of a plant are only peculiar trans- 

 formations of simple stems and leaves. 



This beautiful truth of the transformation or metamor- 

 phosis of plants we owe to the poet Goethe ; for though 

 Linnaeus suggested it rather vaguely in some of his writings, 

 and a botanist named Wolff seems also to have taught it in 

 1766, yet it was Goethe's essay on the ' Metamorphosis of 

 Plants,' published in 1790, which first led naturalists to 

 consider the question. Goethe's work was very little read 

 at first, and he had great difficulty in finding a publisher for 

 it, for it was thought that a poet could not know much of 

 science; but Auguste de Candolle seeing what a new light 

 Goethe's theory threw upon the study of plants, taught it in 

 his works, and then it became gradually known as one of 

 the greatest discoveries in modern botany. 



Fertilisation of Plants by Insects Conrad Sprengel, 

 1750-1816. Another equally important fact was established 

 at this time by the German botanist Sprengel, who was the 

 first to notice the wonderful connection between plants and 

 insects, which Darwin, Hermann Miiller, and others have 

 worked out so minutely. 



Christian Conrad Sprengel was Head-Master at Spandau 



