THE QUARTERLY 
JOURNAL OF SCIENCE. 
JULY, 1878. 
I. THE SENSES OF THE LOWER ANIMALS. 
XPANDING the aspiration of the Scottish poet, most 
fJSj of us at times crave to see, not merely ourselves, but 
the whole world as it appears to the senses of 
others. We cannot help questioning what portion of our 
perceptions is purely objective, depending solely on the 
nature of the things seen, heard, or tasted, and what 
portion, if any, is due to our own subjectivity, and is conse- 
quently liable to vary in different individuals ? For instance, 
we see the flower of a field poppy. It impresses our retina 
with a certain sensation which we have- been taught to call 
“ redness.” We can find in the solar speCtrum, or in 
Chevreul’s chromatic circles, regions which make upon us 
the like impression. Our neighbour, unless affeCted with 
colour-blindness, gives the same name to the effeCt pro- 
duced by the flower upon his sight.* But who guarantees, 
after all, that the impressions made respectively upon him 
and upon us are identical ? Neither of us can make use of 
the optic nerves of the other. Much more strongely does 
this doubt crop up as regards the senses of smell or taste. 
One of the most familiar faCts in daily life is to find one 
man praising an odour or a flavour which is to another 
person simply loathsome. Where lies the difference ? In 
the very impressions made upon the nerves of smell and 
taste, or in the judgment formed by some inward faculty on 
reviewing such impressions ? But if we have already 
grounds for question as to whether our sensuous perceptions 
are identical with those of our fellow-men, the difficulty 
* It has been pointed out that persons suffering from colour-blindness have 
often great facility in accommodating their language to that of their colour- 
discerning neighbours, and thus, unless systematically tested, often escape 
detection. Many persons who are red colour-blind do not merely fail to dis- 
tinguish red from its complementary green, but red light, as light seems to 
make no impression on their retina— a fadt of some importance. 
VOL. VIII. (N.S.) 
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