256 APPENDIX III—LETTERS PUBLISHED IN NATURE. 
In Nature for October 22, 1896, page 605, mention is made of a dis- 
cussion on Neo-Lamarckism at the British Association. In opening 
the discussion, Prof. Lloyd Morgan referred to the importance of 
noting the bearing of certain cases that may be considered as crucial, 
or as nearly crucial as any that we are at present able to obtain, on 
the process by which specific instincts are built up. As illustrating 
this class of cases, he refers to the drinking instinct in newly hatched 
chickens, where the instinctive response begins at the point where the 
teaching of the parent bird would naturally be inadequate. 
The question I wish to raise is whether such observations as this 
can do more than justify the conclusion that life-saving instincts are 
strengthened and established by natural selection. Are they suff- 
cient to show that all permanently inheritable specific characters are 
wholly due to natural selection, or even that natural selection is 
always one of the factors by which any and every permanent character 
hasbeen built up? It seems to me that there are large classes of facts, 
some of which may be found in almost every species we examine, 
which throw doubt upon there being any such inseparable connection 
between natural selection and the inheritance of characters. 
1. Right-handedness and Lejt-handedness. 
The majority of the human species inherit right-handedness. Does 
this prove that right-handedness is better for the race than left- 
handedness? ‘The shells of most snails are coiled in a way that is 
called dextral; but some groups of species are as constantly sinistral 
as most groups are dextral; and of the dextral groups there are cer- 
tain species that are persistently sinistral; others that are nearly 
equally divided between dextral and sinistral forms. Isit necessary 
to believe that for each species that is usually either dextral or sinistral 
there is some vital necessity that would exterminate, or even dimin- 
ish, the species if the character was reversed? A similar class of 
cases is found amongst the different species of flatfish. One species 
persistently lies on the right side, another on the left, and I think it is 
Mr. Cunningham who has told the readers of Nature that there are 
some speciesin which bothforms may occur. In each of these classes 
of cases I am unable to conceive of any advantage gained by the 
species that would not be equally gained if the character under dis- 
cussion was reversed. J} the adaptation to the environment of a flat- 
fish that now lies upon the right side would be equally good in case all the 
individuals of the species lay upon the left side, then (af I rightly under- 
stand the meaning of the terms), natural selection can not be the cause of 
its lying on the right side rather than the left, neither can this character of 
