CHARLES DARWIN-—WEISMANN. 441 
his predecessors at the beginning of the century, and especially from 
his grandfather, Erasmus. It is certain that at 16 he had read the 
“ Zoonomia,” and that he admired it. He relates in his autobiogra- 
phy that, during his student days in Edinburgh, Doctor Grant, after- 
wards a professor at University College, London, spoke to him, in 
the course of a walk, in the most enthusiastic manner of Lamarck and 
his views on evolution. Darwin listened to these views with interest, 
but was in no way impressed or convinced by them. The same is true 
of the “ Zoonomia,” and when he reread it fifteen years later he was 
disappointed in it, “ the proportion of speculation being so large to 
the facts given ” (p. 38). 
Thus Darwin was quite familiar with the views of his grandfather 
and of Lamarck, but it was not these that incited him to follow in 
the same paths; it was rather his own observations of nature that led 
him to abandon his old opinions, and it was only after long years of 
investigation, study, and doubt that he gained sufficient certainty to 
venture on giving his ideas to the world. 
I must refrain from saying more about this journey, which was so 
fruitful for Darwin himself and for science; the two groups of facts 
of which I have spoken were undoubtedly decisive in their effect 
on his conception of nature. In December, 1836, with a wealth of 
great impressions and rich experiences in all the domains of natural 
science, his mind concentrated on the new idea of evolution, Darwin 
returned to his fatherland after an absence of five years. 
Two years after his return he married, bought the estate of Down, 
in the county of Kent, and retired there to spend the whole of the 
rest of his life in constant work, but also in constant fellowship and 
personal touch with the most prominent naturalists of the day, who 
were readily accessible in London. He gradually came to have cor- 
respondence also with many naturalists in other countries. 
His “ chief pleasure and constant occupation ” was his work, which 
sometimes even enabled him to forget the daily discomfort due to 
his health, which had been bad ever since his voyage. From the 
very beginning of the voyage he had suffered from severe and per- 
sistent seasickness, and his constitution had apparently suffered last- 
ing injury, for in his autobiography he often speaks of being unable 
to work because of illness, and sometimes of having lost days and 
weeks, and on one occasion two whole years, from this cause. 
In dealing with his work it is impossible for me to speak of all 
the important volumes he published in the course of his life. The 
first were the results of his voyage, various geological observations, 
and a new theory of the origin of coral islands. 
Up till that time it had been believed that the so-called atolls, or 
lagoon reefs, had been simply built up by the coral polyps from 
the ocean floor until they finally reached the surface, where they 
