x OBITUARY 295 
Of such works published subsequently to 1859, 
several are monographic discussions of topics 
briefly dealt with in the “ Origin,” which, it must 
always be recollected, was considered by the 
author to be merely an abstract of an opus majus. 
The earliest of the books which may be placed 
in this category, “On the Various Contrivances 
by which Orchids are Fertilised by Insects,’ was 
published in 1862, and whether we regard its 
theoretical significance, the excellence of the ob- 
servations and the ingenuity of the reasonings 
which it records, or the prodigious mass of sub- 
sequent investigation of which it has been the 
parent, it has no superior in point of importance. 
The conviction that no theory of the origin of 
species could be satisfactory which failed to offer 
an explanation of the way in which mechanisms 
involving adaptations of structure and function to 
the performance of certain operations are brought 
about, was, from the first, dominant in Darwin’s 
mind. As has been seen, he rejected Lamarck’s 
views because of their obvious incapacity to furnish 
such an explanation in the case of the great 
majority of animal mechanisms, and in that 
of all those presented by the vegetable world. 
So far back as 1793, the wonderful work of 
Sprengel had established, beyond any reasonable 
doubt, the fact that, in a large number of cases, a 
flower is a piece of mechanism the object of which 
is to convert insect visitors into agents of fertilisa- 
