TO THE MEMORY OF 
CHRISTIAN KONRAD SPRENGEL 
FORMERLY RECTOR OF THE GREAT LUTHERAN TOWN-SCHOOL IN SPANDAU 
BORN AT BRANDENBURG ON THE HAVEL IN 1750 
DIED AT BERLIN ON APRIL 7TH, 1816 
AND 
DR. HERMANN MULLER 
FORMERLY PROFESSOR IN THE REALSCHULE AT LIPPSTADT IN WESTPHALIA 
BORN AT MUHLBERG IN THURINGIA ON SEPTEMBER 23RD, 1829 
DIED AT PRAD IN THE TYROL ON AUGUST 25TH, 1883 
CurisTIAN KonrapD SpRENGEL and HERMANN MULLER were characterized 
by untiring diligence and ardour for research, incomparable powers of obser- 
vation, and extraordinary acuteness in the interpretation of the phenomena 
of Flower Pollination. With this was united in a conspicuous degree the 
ability to describe their discoveries in a most admirable manner. Their 
fundamentally important works on Flower Pollination are now, therefore, 
an inexhaustible source of instruction and enjoyment, as they must always be. 
This book, which shows the present position of the Science of Flower 
Pollination, is dedicated to the memory of these two great investigators. 
