PUBLICATIONS. 93 



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 Do- 

 mestication ' was begun, as already stated, in the be- 

 ginning of 1860, 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 

 productions. 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 hypothesis 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 

 1838, convinced that species were mutable productions, 

 I could not avoid the belief that man must come under 

 the same law. Accordingly I collected notes on the 



