HISTORICAL DEVELOPMENT OF FLOWER POLLINATION 21 



und die gegenseitigen Anpassungen beider' (Leipzig, 1873), which meanwhile appeared, 

 was of remarkable importance for the study of Flower Pollination. It was followed in 

 1881 by Mailer's second great work, ' Alpenblumen,' and in 1878-1882 by his third— 

 ' Weitere Beobachtungen fiber die Befruchtung der Blumen durch Insekten.' These 

 works embrace not only an amazing number of individual observations with reference 

 both to the floral arrangements of many hundreds of plants and also to the visits 

 of many thousands of insects, but they also furnish evidence for the floral theory 

 established by the author. The principles enunciated by Knight, Darwin, Hildebrand, 

 and Delpino offered no explanation of the numerous known instances of fruitful 

 self-pollination, including cases of cleistogamy. For the one-sided 'Law' of the 

 above-named investigators — a Law that was not universally proved, — MUller substituted 

 the following statement, the direct proof of which rested on Darwin's experiments, 

 while the indirect proof was based on the floral arrangements of plants in general, 

 and, more particularly, on adaptations in the flowers themselves : Whenever progeny 

 resulting from, crossing comes into serious conflict with the offspring resulting from 

 self-fertilization, the former is victorious. Only where there is no such struggle for 

 existence can self fertilization often prove satisfactory for many generations. 



That direct and indirect proofs attest the correctness of this great law of life 

 has already been stated. They are given as follows by Hermann Mfiller (in 

 'Alpenblumen,' pp. 474-5): — 'In the flowers investigated in this connection, it 

 appeared, as first shown at any length in 'Die Befruchtung der Blumen durch 

 Insekten,' to be a general rule, offering only a few easily explained exceptions, that 

 flowers to which insect visits are constant and sufficient, are adapted exclusively 

 for crossing by the insects, and that, oq the contrary, in proportion as insect visits 

 are uncertain, the floral arrangements permit or favour spontaneous self-fertilization. 

 It appears from the direct experiments of Darwin, as weU as from the pollination 



University of Halle to study Natnral Science. He devoted himself here chiefly to Geology, to which 

 he also applied himself enthusiastically in Berlin, during his stay there from 1849 to 1852. In 1852 

 he passed the Examination pro Facultate docendi and spent the following winter in the bouse of his 

 parents. In 1853 he made his first journey to the Alps, this being chiefly undertaken in furtherance 

 of his geological studies, though he also did something in the way of collecting plants and insects. 

 From Michaelmas, 1853, till the following Michaelmas, MUller spent his year of probation in the 

 Friedrich-Wilhelm Gymnasium at Berlin. Next winter he took the place of a teacher in Schwerin 

 who was sick. His first journey in the Alps had aroused in him an appreciation for the rich flora 

 and fauna of the Highlands, and in 1855 he undertook his second alpine journey, and this was 

 specially devoted to Botany and Entomology. In the same year Miiller was called to the Realschule 

 in Lippstadt, which was then in course of formation. In 1856 he was definitely placed on the staff 

 of this institution; in 1865 he became upper-master; and in 1883 he received the title of Professor. 



The ' Origin of Species,' and Darwin's book on Orchids had so great an influence on Hermann 

 Miiller, that from 1 866, the year in which he became acquainted with these works, he devoted his 

 knowledge, his energy, and his power of research wholly to Pollination. In 1873 appeared his first 

 great work, ' Die Befruchtung der Blumen durch Insekten ' ; in 1 88 1 his second, ' Die Alpenblumen ' ; 

 from 1878 to 1882 his third, which forms a completion to the first, ' Weitere Beobachttmgen iiber die 

 Befimchtung der Blumen durch Insekten.' Hermann Miiller died on August 25, 1883, of pulmonary 

 disease, while travelling in the Tyrol in pursuit of Science, and for the benefit of his health. A full 

 account of his life, and of his services to Pedagogy, and more especially to Pollination, is given by 

 F. Ludwig in the Bot. Centralbl., 1884, vol. xvii, pp. 393-414, under the title ' Das Leben und Wirken 

 Professor Dr. Hermann Miiller's.' See also E. Krause in the work, ' Hermann Miiller von Lippstadt. 

 Ein Gedenkblatt. Lippstadt, 1 884.' 



