64 SECRETS OF ANIMAL LIFE . 
practical, esthetic, and imaginative. This is surely 
true of shells. Throughout the greater part of the 
world simple peoples have used various shellfish 
(an abhorrent word to the zoologist) for food; and 
this, of course, continues, whether in oysters, which 
Huxley likened to “gustatory flashes of summer 
lightning,” or, at the other pole of expenditure, in 
winkles, which require no apology. And apart from 
edibility and the use of mollusks as bait, many shells 
have proved of practical service to man as instru- 
ments or parts of instruments. Secondly, the 
decorative or emotion-exciting value of shells has 
been appreciated all over the world, the waist- 
band of cowries and the necklace of pearls having 
the same merit of great beauty, enhanced in both 
cases, no doubt, by monetary and other associations. 
And, thirdly, it seems quite certain that infectious 
imaginative suggestions, perhaps rather fanciful 
and arbitrary to start with, have given certain shells 
psychological value as symbols, charms, and 
amulets. We venture to think that some anthro- 
pologists who have emphasized the symbolism of 
certain shells, notably cowries, have tended to 
underestimate the associated practical and sensory 
values. We fancy that the wide diffusion of a 
recognition of the symbolic significance of certain 
shells was partly due to their correlated beauty and 
usefulness. In any case, the three factors must have 
co-operated, as some examples will show. 
One of the many undated human inventions was 
that of the shell-trumpet. It may have been 
