8o PLANT HYBRIDIZATION BEFORE MENDEL 



five years of minute and extensive observations and studies, in 

 a folio volume with twenty-five plates, which contained hundreds 

 of detailed and accurate illustrations of flowers and their parts. 

 This famous work, "Das entdeckte Geheimniss der Natur im Bau 

 und in der Befruchtung der Blumen," was based upon the thor- 

 oughgoing observation and investigation of nearly live hundred 

 species. 



Through lack of funds Sprengel was prevented from publish- 

 ing the second part of his work, which led him, toward the end 

 of his life, to give up botany altogether, and devote himself to 

 classical studies. During his years of retirement in Berlin, he gave 

 lessons in the classics and in botany for recreation, and on Sun- 

 days conducted botanical excursions in the neighborhood of Berlin 

 for small fees. 



On account of the dry and formal character of the botanical 

 science of his time, Sprengel's work remained unnoticed for forty- 

 three years after his death. 



The first serious mention of it in scientific literature appears 

 to have been that made by Darwin, in the "Origin of Species" in 

 1859. (6th ed. 1895, p. 119.) 



Sprengel is described as a man averse to the conventional flat- 

 teries of life, and of a rather recklessly open type of character. 

 In his Berlin excursions he is described as awakening attention 

 through the wealth of his knowledge and his inwardly spiritual 

 character, and as arousing interest alike in all the objects of 

 nature, — an inscription on a gravestone, the construction of a 

 windmill, the course of the stars, and the body of a plant. Dur- 

 ing Sprengel's Spandau period, it is stated, a large portion of his 

 thirteen years of official duty was filled with an almost unbroken 

 chain of events involving insubordination, quarrels with the au- 

 thorities, and friction with the parents of the pupils, which cir- 

 cumstances led him to be described by a local chronicler as "in- 

 human in his punishments, arbitrary in his teaching, stubborn, and 

 little religious." The whole truth appears to have been that Spren- 

 gel was a man of a large and powerful nature, with considerable 

 intellectual gifts, rich knowledge, and aware of his own state of 

 advancement, but uncompromising, and, from having been forced 

 into too confined and narrow an environment in which his ideas 

 and prepossessions found little opportunity for expression, his na- 



