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mutual separation of allied species ; which produces a 
co-operation of very distinct species, enabling them to 
resist the disabilities of their outward conditions ; which, 
in no one of its different phases produces the transmuta 
tion of species by Natural Selection, is cited as the 
strongest argument to prove the efficient and all-embracing 
influence of that supposed law of nature. 
(b) NO ORGAN OR INSTINCT EXISTS FOR THE SOLE BENEFIT OF 
ANOTHER SPECIES. 
“ Bear ye one another’s burdens.” 
“ Every man must bear his own burden.” 
—Paul. 
The second argument urged by Mr. Romanes is based 
upon the fact that “ among all the millions of structures 
and instincts which are so invariably and, for the most part, 
so wonderfully adapted to the needs of the species present 
ing them, we cannot find a single instance, either in the 
vegetable or animal kingdom, of a structure or an instinct 
which is developed for the exclusive benefit of another 
species.”* This argument does not, however, apply to the 
cases in which “ a structure or an instinct is of primary 
benefit to its possessor and then becomes of secondary 
benefit to some other species on account of the latter 
being able in some way or other to utilise its action.”f 
“From the first Darwin invited criticism to adduce a single 
instance, either in the vegetable or animal kingdom, of a structure 
or an instinct which should unquestionably be proved to be of ex 
clusive use to any species other than the one presenting it. He 
* Darwin and After Darwin, p. 286. 
t Ibid. p. 288.