400 
Colour and its Recognition . rjune, 
In speaking of the generation of pigments Mr. Allen 
quotes with approval the declaration of Mr. Lowne,* that 
these substances are apparently due to the waste-products 
of other organs, and do not take away anything from the 
effective energies of the system. It might, perhaps, be 
asked how this view agrees with the one put forward in an 
earlier part of his work, where the production of colour is 
connected with the expenditure of energy ? We fully admit 
the very high proportion of nitrogen present in feathers, and 
we recognise the faCt that those animals — inseCts, birds, 
and reptiles — which are most richly coloured excrete uric 
acid to a notable extent. At the same time it must be ad- 
mitted that the most beautiful colouring of such animals is 
due not to any pigment, but to the interference of light 
arising from the micro-mechanical texture of the feathers, 
wing-scales, elytra, &c. 
Concerning “prohibitive” or “warning” colour, the 
author declares himself somewhat sceptical. As regards 
the eggs of birds he suggests that “ the colouration may 
aCt as a supplementary allurement to the instinCt of incu- 
bation.” But how if the nest, as occurs in not a few 
species, such as the kingfisher, is absolutely dark within ? 
The concluding chapters of the work treat of the colour- 
sense in man, of the esthetic value of colour, and of the 
growth of the colour-vocabulary. By testimony collected 
through the aid of consuls, missionaries, and others, from 
semi-civilised and savage tribes, it is shown that the colour- 
sense is universal. By the evidence of gems and glass and 
stone beads, obtained from the lake-dwellings of Switzerland 
from barrows of the Stone Age, and of pottery from Dr. 
Schliemann’s excavations at Mycsena, a cumulative proof is 
furnished that this same sense is of no recent growth. 
Philosophy of Education, p. 75. 
