PUBLICATIONS. 



75 



of this paper cost me four months ; but I was so unwell when 

 I received the proof-sheets that I was forced to leave them 

 very badly and often obscurely expressed. The paper was 

 little noticed, but when in 1875 it was corrected and published 

 as a separate book it sold well. I was led to take up this sub- 

 ject by reading a short paper by Asa Gray, published in 1858. 

 He sent me seeds, and on raising some plants I was so much 

 fascinated and perplexed by the revolving movements of the 

 tendrils and stems, which movements are really very simple, 

 though appearing at first sight very complex, that I procured 

 various other kinds of climbing plants, and studied the whole 

 subject. I was all the more attracted to it, from not being at 

 all satisfied with the explanation which Henslow gave us in 

 his lectures, about twining plants, namely, that they had a 

 natural tendency to grow up in a spire. This explanation 

 proved quite erroneous. Some of the adaptations displayed 

 by Climbing Plants are as beautiful as those of Orchids for 

 ensuring cross-fertilisation. 



My ' Variation of Animals and Plants under Domestica- 

 tion ' was begun, as already stated, in the beginning of i860, 

 but was not published until the beginning of 1868. It was a 

 big book, and cost me four years and two months' hard labour. 

 It gives all my observations and an immense number of facts 

 collected from various sources, about our domestic produc- 

 tions. In the second volume the causes and laws of variation, 

 inheritance, &c, are discussed as far as our present state of 

 knowledge permits. Towards the end of the work I give my 

 well-abused hypothesis of Pangenesis. An unverified hypothe- 

 sis is of little or no value ; but if any one should hereafter be 

 led to make observations by which some such hypothesis 

 could be established, I shall have done good service, as an 

 astonishing number of isolated facts can be thus connected 

 together and rendered intelligible. In 1875 a second and 

 largely corrected edition, which cost me a good deal of labour, 

 was brought out. 



My 'Descent of Man' was published in February, 1871. 

 As soon as I had become, in the year 1837 or 1^38, convinced 



