HftT.^US.IV)£U 
io INTRODUCTION 
with which he came into contact, and after describing it in 
The Native Tribes of Central Australia (published jointly with 
F. J. Gillen) he adduced some reasons for thinking that this 
system of group relationship was derived from a system of 
group marriage, of which he believed traces to survive in 
certain existing customs regulating the relations of the sexes 
among the Australian aborigines. But when he treated of 
the same subject in his later work, The Arunta , which is in 
substance a revised and enlarged edition of the account 
which he had given of that tribe in The Native Tribes of 
Central Australia , he entirely omitted this suggestion as to 
the origin of the Classificatory System of Relationship, and 
confined himself to describing the facts of the system in a 
fuller form, leaving his readers to draw their own inferences. 
Apparently he had come to the conclusion that the discussion 
of origins should form no part of the description of a particular 
tribe. But I have no reason to think that he ever abandoned 
the theory, for he vigorously maintained it in a personal discus¬ 
sion with Professor Edward Westermarck which took place 
at my rooms in the Temple long after the publication of 
The Native Tribes of Central Australia^ but before the publica¬ 
tion of The Arunta . Elsewhere in his w r ritings, so far as I 
remember, he has uniformly abstained from the discussion 
of origins, and in so doing he has given proof of his scientific 
caution. The whole bent of his mind was indeed to observa¬ 
tion rather than to speculation; he collected an immense mass 
of new and important facts, but in general he left the inter¬ 
pretation of them to others. He laid the foundations of the 
science of man in a series of exact observations; it will be for 
future inquirers to complete the structure by rearing on his 
foundations a solid edifice compacted of sound inductions. 
That may prove a task which will demand the labours of 
generations yet to come. 
Among the high qualities which Spencer brought to the 
