August 6, 1897.] 
sibly orange and violet. At first the scientific 
method would seem to be to choose from the 
spectrum itself and locate those colors ideally, 
but we wish concrete surfaces of paper or 
similar material for our working standards, and 
if we choose our colors thus can we match 
them in practice? Chromolithography can do 
wonders and can nearly match a spectrum 
color. The objection, however, to such work- 
ing standards is that each lithographer, and 
indeed the same one at different times, will 
succeed to different degrees, so that a slight 
variation in color, luminosity and saturation is 
inevitable. 
Moreover, practically all the lithographic inks 
used in such work will fade, and fade surely and 
badly, a fatal objection to their use as stand- 
ards. Another way to choose the working 
colors is to have in mind the pigment to be used 
in representing the color, as well as the par- 
ticular wave-length desired. 
It was the apparent advantages of the latter 
method, as well as the advice of good authori- 
ties, which led us to follow it in the choice of 
our working standards when we were asked to 
prepare the material in the ‘Standard Diction- 
ary.’ In our choice we were influenced by the 
following considerations: Emerald green (Paris 
green) is of the desirable color, is very uniform 
and is easily obtained; similar advantages 
recommend artificial ultra-marine blue. Fora 
red, evidently a vermilion should be taken, 
and in selecting ‘English vermilion’ we may 
have erred, but believe it the most uniform and 
best suited. Mineral orange seemed very nearly 
identical in different samples, and was adopted 
since its color was that desired. As to chrome 
yellow it may be very truly urged that there are 
great variations, but when the samples are 
chosen by wave-length the character of the 
yellow is identical. The lack of a good, per- 
manent violet pigment, as well as the apparent 
lack of the necessity of having a violet standard. 
induced us to omit it. These pigments can be 
obtained everywhere, and for most purposes true 
enough to wave-length. They fade but slightly, 
if at all, and when mixed with thick gum arabic 
solution and applied like an oil paint to com- 
pletely cover the surface their total luminosity 
and saturation is always practically the same. 
SCIENCE. 215 
They thus furnish working standards which can 
be reproduced by anybody in any part of the 
world with great accuracy if necessary. To- 
gether with white cardboard and lamp black car- 
ried in shellacthey enable an observer to produce 
practically any color, shade, hue or tint, by 
combining them as Maxwell disks. 
Other pigments, other colors,may finally prove 
more worthy of general and final adoption, but 
it seems to us that the considerations which in- 
fluenced us most seriously influence the final 
selection. 
No doubt Mr. Pillsbury regretted that his 
system was not adopted for the ‘ Standard Dic- 
tionary’, but that should not have induced him 
to insinuate that we copied his system, or to 
refer to a typographical error as ‘an uninten- 
tional blunder.’ We have no desire to be- 
little the work of Milton Bradley or Mr. Pills- 
bury, for they are doing much for the introduc- 
tion of scientific methods into color study, but 
it did not seem best to us to attempt to define 
all colors, using only two colored discs at a time, 
and we do not believe that any lithographed 
surfaces should be adopted as ultimate stand- 
ards, even though they may prove best adapted 
to educational purposes. 
W. HALLOCK, 
R. Gorpdon. 
THE TERM ‘INTERNAL SECRETIONS.’ 
To THE EDITOR OF SCIENCE: At the begin- 
ning of his interesting paper on ‘The Physiology 
of Internal Secretions,’ SclENCE, No. 132, Dr. 
Howell says: ‘‘ We owe the term ‘ internal secre- 
tions’ to Brown-Séequard, by whom it was first 
used in published communications dating from 
1891.’’? It may be worth while to note that 
Claude Bernard in his famous ‘ Rapport sur les 
progrés et la marche de la physiologie générale 
en France,’ 1867, says, at page 73, ‘‘ La cellule 
sécrétoire, au contraire, attire, crée et élabore 
en elle méme le produit de sécrétion, qu’elle 
verse soit au dehors sur les surfaces muqueuses, 
soit directement dans la masse du sang. J’ai 
appelé sécrétions externes celles qui s’écoulent 
en dehors, et sécrétions internes celles qui sont 
versées dans le milieu organique intérieur.’’ 
C. B. DAVENPORT. 
Mus. Comp. Zoou., July 26, 1897. 
