Sao The American Naturalist. [J^ine, 
one boot is amply sufficient to make a trail which the animal 
can recognize as mine, the scent is not able to penetrate a 
single layer of brown paper. Furthermore, it would appear 
that in following a trail this bitch is ready at any moment to 
be guided by inference as well as by perception, and that the 
act of inference is instantaneous. Lastly, the experiments 
show that not only the feet (as these effect the boots) but like- 
wise the whole body of a man exhales a peculiar or individual 
odor, which a dog can recognize as that of his master amid a 
crowd of other persons ; that the individual quaHty of this 
odor can be recognized at great distances to windward, or, m 
calm weather, at great distances in any direction ; and that 
this odor is not overcome by anise seed." — ZooL, Anz., No. 
242. 
Mind and Consciousness. — To the Editor of the Open 
Court : You and Mr. Hegeler have expressed the desire (in 
a letter, December 31, 1887), to know how it happened that 
in my friendly contention with Professor Cope I have used 
" consciousness " and " mind " synonymously. I did so partly 
out of courtesy to my adversary, who habitually makes use of 
the phrase " mind or consciousness," and partly to carry on 
the discussion as much as possible on the basis given by him- 
self. 
Allow me, however, to indicate as briefly as possible how 
I myself distinguish "consciousness" from "mind." "Con- 
sciousness " is that state of our being in which we are aware 
of what is usually classified as sensations, perceptions, emo- 
tions, thoughts and volitions. When we are thoroughly asleep 
or in a swoon we are not aware of such affections, and are 
consequently not conscious. 
Consciousness, of course, can be only a present phenome- 
non, a manifestation taking place within us at the very mo- 
ment. When we are conscious of something that has occurred 
in the past, this retrospective consciousness takes place like- 
wise only in the moment of present awareness. The same 
holds good with prospective consciousness. We foresee the 
future only as content of our present consciousness. 
I have called this one, all-comprising moment of conscious 
realization " the mental presence, " and have repeatedly 
pointed out that its contents vanish from moment to moment 
into nothingness, and are as constantly reconstituted under 
kaleidoscopic changes, from a persistent vital matrix. Con- 
