262 THE POPULAR SCIENCE MONTHLY. 



fluenced his thoughts. He remarks that he ' can understand the grada- 

 tion only as a prolonged struggle against unfavorable conditions.' " 

 The President of the Geological Society has said that, "looking at 

 the general mass of Mr. Darwin's results, I can not help considering 

 his voyage around the world as one of the most important events for 

 geology which has occurred for many years." Professor John W. 

 Judd, noticing the works of this series in a group, said, in 1877, " Stu- 

 dents of Mr. Darwin's earlier geological writings must all have been 

 impressed by the powers of minute observation, the acumen in testing, 

 and the skill in grouping data, and the boldness and originality in 

 generalization which distinguished their author ; for these character- 

 istics are no less distinguished in the theory of coral reefs than in that 

 of natural selection " ; and " these ' Geological Observations ' are well 

 worthy to take their place in the long series of the author's contribu- 

 tions to the doctrine of descent side by side with those more widely 

 known works on different dej^artments of zoology and botany which 

 have been published subsequently to the ' Origin of Species.' " 



His most important work on zoology, " A Monograph of the Family 

 Cirripedia," was published by the Ray Society, 1851 to 1853. It gave 

 accurate determinations of every recognized species of the animals 

 known as barnacles and sea-acorns; and was shortly afterward followed 

 by another monograph on the fossil species of the same family, which 

 was brought out by the Philosophical Society. All of these works 

 each of which was, as the estimates we have quoted indicate, of the 

 first importance in itself, and each of which is a standard to this day 

 were but as preliminaries to the culminating achievement of Mr. Dar- 

 win's life, the exposition of the doctrine of the origin of species and 

 development by natural selection, as given in the series of works on 

 " The Origin of Species by Means of Natural Selection ; or, the Pres- 

 ervation of Favored Paces in the Struggle for Life" (1859) ; "The 

 Variations of Plants and Animals under Domestication" (1867), and 

 "The Descent of Man and Selection in Relation to Sex" (1871) ; and 

 in the numerous special works in which he has made various particular 

 phenomena of animal and vegetable life illustrate and re-enforce his 

 great doctrine. The views expressed and defined in these works, al- 

 though, now that they have " come of age," they have sensibly and 

 profoundly affected the whole world of thought, were a surprise. 

 Scientific men received them hesitatingly or with incredulity ; those 

 who were not scientific with displeasure. Yet they were not wholly 

 novel ; for Aristotle, Goethe, Mr. Darwin's grandfather, and others, 

 had suggested similar hypotheses, and Mr. Wallace had independently 

 reached conclusions very like those enunciated by Mr. Darwin. They 

 have had to make their way against the prepossessions of the minds 

 to whom they appealed, and against the prejudices which those pre- 

 possessions awakened when they were assailed. 



Gradually the theory of descent gained acceptance among the 



