84 CHARLES DARWIN. 



Other marsh and bog plants, in relation to their insect prey. 

 In the second he shows that nature abhors self-fertilization, because 

 it ultimately leads to degradation and extinction, and that cross 

 fertilization produces the best offspring in respect of growth, 

 strength, and fertility, proving that in spite of the fact that most 

 flowers are hermaphrodite, there is usually some provision for the 

 transference of pollen from the flowers of one plant to another of 

 the same species. In the third he proved that the different 

 positions of stamens and pistil in the flowers of even a single plant, 

 in such cases as those of Primrose, Cowslip, Loose-strife, and Flax, 

 was really in order to ensure cross-fertilization, and to render self- 

 fertilization impossible, thus securing an abundant, healthy, and 

 vigorous offspring. 



In 1880, when 71 years old, Darwin issued a book on the 

 Powe7- of Movement in Plants. Here he traced the windings 

 of the tiniest rootlets and stems, and assigned to these their cause 

 and effect ; still further, he investigated the wonderful phenomena 

 seen in such plants as Mimosa (the Sensitive plant), and others 

 whose leaves are said to " sleep," and taught us the meaning of 

 the " sleep " in all these cases, as well as leading us to see the 

 relation of the opening and closing of flowers to difterent times of 

 day or night, to varying seasons, and to geographical habitat. 

 No more interesting, volume came from his pen than this one 

 from many points of view. 



Finally in 1881, only a short time before his death, his last 

 work on the Formation of Vegetable Mouldy to which I have 

 previously referred, was in a sense as much related to botanical 

 science as it was to that of Geology. 



Zoology. — The Naturalisfs Voyage of course abounds 

 with zoological facts and especially deals with geographical distri- 

 bution of species, but in 185 i and 1844 were published the only 

 purely zoological works that Darwin wrote. These were 2 volumes 

 issued by the Ray Society, one on Recent Barnacles, and a 

 second on the Fossil species of the same family. They were 

 together called A MotiograpJi of the Cirripedia and proved 

 abundantly that had he resolved to devote his life to pure Mor- 

 phology only, he would indubitably have taken a foremost place 

 as an anatomical investigator. 



