of a plant enables botanists, but no others, to
distinguish it. Thus the natural character of signs, the universal
significance which is their peculiarly distinctive feature, may
and often does become lost. From the operation of the principle of
independent and individual abbreviation inherent in all sign language,
without any other cause, that of the Indians must in one or two
generations have become diverse, even if it had in fact originated
from one tribe in which all conceptions and executions were absolute.

_ARE SIGNS CONVENTIONAL OR INSTINCTIVE?_

There has been much discussion on the question whether gesture signs
were originally invented, in the strict sense of that term, or whether
they result from a natural connection between them and the ideas
represented by them, that is whether they are conventional or
instinctive. Cardinal Wiseman (_Essays_, III, 537) thinks that they
are of both characters; but referring particularly to the Italian
signs and the proper mode of discovering their meaning, observes that
they are used primarily with words and from the usual accompaniment of
certain phrases. "For these the gestures become substitutes, and then
by association express all their meaning, even when used alone."
This would be the process only where systematic gestures had never
prevailed or had been so disused as to be forgotten, and were adopted
after elaborate oral phrases and traditional oral expressions had
become common. In other parts of this paper it is suggested that
conventionality chiefly consists in abbreviation, and that signs are
originally self-interpreting, independent of words, and therefore in a
certain sense instinctive.

Another form of the above query, having the same intent, is whether
signs are arbitrary or natural. The answer will depend upon what the
observer considers to be natural to himself. A common sign among
both deaf-mutes and Indians for _woman_ consists in designating the
arrangement of the hair, but such a represented arrangement of
hair familiar to the gesturer as had never been seen by the person
addressed would not seem "natural" to the latter. It would be
classed as arbitrary, and could not be understood without context
or explanation, indeed without translation such as is required from
foreign oral speech. Signs most naturally, that is, appropriately,
expressing a conception of the thing signified, are first adopted and
afterwards modified by circumstances of environme