APRIL 7.] THE NEW ZEALAND GAZETTE. 595

the colours (1-5) of the plate. If the examinee were
allowed to depart from the narrow limits every shade of
green could be included, the result of which would be that
he would prefer to select all the vivid shades, and thus avoid
the dangerous ground where his defect would certainly be
discovered. This is why it is necessary to oblige him to keep
within certain limits, confining him to pure-green speci-
mens, and, for greater security, to recommend him to select
especially the lightest shades; for, if he keeps to the darker
shades, as many try to do, he readily passes to other tones,
and loses himself on foreign ground, to the great loss of time
and of the certainty of the test. What we have just said of
green applies also, of course, to purple (test II.a).

The principle of our method is to force the examinee to
reveal, by an act of his own, the nature of his chromatic
sense.

Now, as this act must be kept within certain limits, it is
evident that the Examiner must direct him to some extent.
This may present, in certain cases, some difficulty, as he
will not always be guided, and does either too much or too
little. In both cases the Examiner should use his influence
in order to save time and gain certainty, and this is usually
very easily done. This intervention is, of course, intended
to put the examinee in the true path, and is accomplished
in many ways, according to the case in point.

We will here mention some of the expedients we have
found useful:—

(A.) Interfering when the Candidate selects too many Colours.

It is not always easy to confine the candidate within the
proper limits. In the first test he easily slips a yellow-green
or blue-green skein among the others, and as soon as there is
one others usually follow; and it thus happens that in a few
moments he has a whole handful of yellow-green, a second
of blue-green, a third of both these shades at the same time.
Our procedure has assisted us in more than one case of this
kind.

(a.) When the person examined has begun to select shades
of one or several other colours than those of the sample, his
ardour is arrested by taking from him the handful of skeins
he has collected and asking him whether his eye does not
tell him there are some which do not match the others, in
which case he is told he may restore them to the pile. He
then generally proceeds in one of the following manners:—

1. He rejects, one after the other, the incorrect skeins, so
   that only the correct remain, which is often only the sample
   skein. He is shown what mistake he has made, and he is
   told only to select skeins of the same hue as the specimen,
   although they may be lighter or darker. If his first error
   arose only from a misconception, or want of practice in
   handling colours, he begins generally to understand what he
   has to do, and to do properly what is required of him.

2. Or else he selects and rejects immediately the test-
   skein itself. This proves that he sees the difference of
   colour. He is then shown the test-skein as the only correct
   one, and is asked to repeat the trial in a more correct man-
   ner. He is again put on the right track, as just before, and
   the trial proceeds rightly, unless the error arose from a
   defect in colour-sense. Many seem, however, to experience
   a natural difficulty in distinguishing between yellow-green
   and blue-green, or the dull shades of green and blue. This
   difficulty is, however, more apparent than real, and is cor-
   rected usually by direct comparison. If the method requir-
   ing the name of the colour to be given is used, a number of
   mistakes may be the result. If a skein of light-green and
   light-blue alone are presented to him, and he is asked to
   name them, he will often call blue green and green blue.
   But if, in the first case, a blue skein is immediately shown
   him, he corrects his mistake by saying, “This is blue and
   that green.” In the last case the same thing happens muta-
   tis mutandis. This is not the place for an explanation. It
   must suffice to say that the error is corrected by a direct
   comparison between the two colours.

(b.) Another Process.—If the candidate place by the side
of the sample a shade, for instance, of yellow-green, the
Examiner places near this another shade in which there is
more yellow, or even a pure yellow, remarking at the same
time that if the first suit the last must also. The candidate
usually dissents from this. He is then shown, by selecting
and classing the intermediate shades, that there is a grada-
tion, which will diverge widely if logically carried out as he
has begun. The same course is followed with colours of the
blue shades, if the blue-green were first selected. He sees
the successive gradations, and goes through with this test
perfectly, if his chromatic sense is correct.

To ascertain further whether he notices the tints of yellow
and blue in the green, we can ourselves take the yellow-
green and blue-green and ask him if he sees any difference in
colour between them. We can judge by his answer of his
sense with regard to these shades, and the object of this in-
vestigation is accomplished.

It results from all this that many who are finally con-
sidered to have a normal chromatic sense may occasionally
cause embarrassment. In the main, the normal observer of
this kind causes greater loss of time than the colour-blind.
It is astonishing to see with what rapidity the colour-blind
betray their defect. At least, it is found in the majority of
the cases examined by us that the first skein of wool selected
from the pile by the colour-blind in the first test was one of
the “colours of confusion.”

(B.) Interfering when the Candidate selects too few Wools.

Those who evince too great slowness also require the inter-
ference of the Examiner in another manner. We can lay
aside here those cases in which, at the sight of the com-
plex colours of the heap of wool, the candidate finds it dif-
ficult to select a skein resembling the sample in a
collection where all the particular colours seem to differ
from each other, and in consequence declares immediately
that he can find none resembling the specimen. He is then
told that an absolute resemblance is not demanded, and that
no one asks impossibilities; that time is limited, many are
waiting, &c. But there are people who—from natural slow-
ness, from being unaccustomed to such business, from fear
of making mistakes, especially if they have been previously
examined and been suspected of colour-blindness, or from
many other motives—proceed with the greatest caution.
They do not even wish to touch the wool; or they search,
select, and replace with the greatest care all the possible
skeins without finding one corresponding with the sample,
or that they wish to place beside it. Here, then, are two
cases—on the one hand, too much action with the fingers,
without result; on the other, too little action. The Examiner
is forced to interfere in both cases.

(a.) In the case of too much manual action, without cor-
responding practical result, the Examiner must be careful
that the eye and hand of the candidate act simultaneously
for the accomplishment of the desired end.

Some people forget that the hands should be subservient
to the eye in this trial, and not act independently. Thus
they are often seen to fix their eyes on one side while their
hands are engaged on the other. This should be corrected,
so as to save time and avoid further labour. The candidate
should be told to cross his hands behind his back, to step
back a pace, and quietly consider all the skeins, and, as
soon as his eye has met one of those for which he is looking,
to extend his hand and take it. The best plan is to advise
him to look first at the sample and then at the pile, and to
repeat this manœuvre until his eyes find what he is looking
for.

This plan generally succeeds when nervousness from over-
anxiety causes his hands to tremble; but it is not always
easy to induce him to keep his hands behind his back until
the moment for taking the skein in question.

(b.) In cases of great caution, the trial is hastened if the
Examiner come to the assistance of the candidate by hold-
ing above the pile one skein after the other, and requesting
him to say whether it resembles the colour of the sample
or not.

In cases where any one suspected of colour-blindness has
remained some time to see the trial of others, and where, as
often happens, he has remarked the skeins belonging to a
required shade, he may, of course, profit by it in his own
trial. But this can be prevented by shuffling the skeins.

It may be regarded as an advantage of this method that
it has at command a great variety of resources. We have
by no means mentioned all; and yet many who have only
read this description will probably reproach us with having
devoted ourselves too much to details which seem to them
puerile. But we believe that those who have examined the
colour-sense of a great number of persons, and acquired
thereby considerable experience, will think differently.

We are convinced that time is saved by the means we have
described, and a more certain result obtained; whilst a
practised surgeon, who has become to a certain degree a
virtuoso, will accomplish his object quicker and surer by
such means than one who neglects them. Recent expe-
rience fully confirms this. All those who have familiarised
themselves with this method, and have had experience with
colour-blindness, and of whose competence there can be no
doubt, report, without exception, that it is to be fully de-
pendent on—the most practical and the best.

An advantage of the method was shown to be that those
who were to be examined could be present and see each
individual tested without this interfering in the least with
the certainty of the result. The individual test is even
hastened thereby. The colour-blind, and even the normal-
eyed who are not familiar with colours, are generally rather
shy about being tested, in whatever way it is done. As the
method, however, is carried out, they have more confidence.
The majority are even amused. The old adage holds true
here, that it is easier to find fault than to do it yourself.
The surgeon, who watches not only the examined, but also
those around, can often see from their faces how closely the
latter observe the person being tested, when he takes out
the wrong colours, as also when he neglects the right ones