SCIENCE. 
8i 
which it flows, while at the same time a record is made of 
the volume of the fluid thus displaced. 
The more important work going on in the laboratory at 
the time of my visit consisted of experiments in regard to 
respiration, with special reference to the functions of the 
glottis and epiglottis, and trials of disinfectants with a 
view to ascertaining the temperature necessary to kill 
germs. A series of experiments was also in progress for 
testing the porosity of various stones used in building. 
The results of the original work performed here have 
been recently published, together with an account of the 
physical apparatus in use at the school. Accounts of the 
most important investigations carried on during the last 
year are contained in the following papers : “ Growth as a 
Function of Cells: Preliminary Notice of Certain Laws 
of Histological Differentiation,” by C. G. Minot ; “ Effects 
of the Respiratory Movements on the Pulmonary Circula- 
tion,” by H. P. Bowditch, M. D., and G. M. Garland, M. 
D.; “Pharyngeal Respiration,” by G. M. Garland, M. D.; 
“Functions of the Epiglottis in Deglutition and Phona- 
tion,” by G. L. Walton. This paper shows that the re- 
moval of the epiglottis does not seriously affect deglut. - 
tion, and therefore it is not necessary for that process. 
The epiglottis, however, plays an important part in form- 
ing and modifying the voice, taking different positions 
during vocalization, changes of pitch, quality, and in- 
tensity. 
In the chemical laboratory I found that Professor Wood 
had been examining the water-supply of Cambridge ; and 
was then engaged in the investigation of the extent to 
which arsenic is being used in the manufacture or orna- 
mentation of articles in general use, such as wall-paper, 
confectionery, playthings, etc. The results of this work 
will be published in the next report of the State Board of 
Health. Professor Wood is also writing the addition to 
“Ziemssen’s Cyclopaedia” on the subject of toxicology. 
Dr. William B. Hills was engaged upon a special inves- 
tigation in regard to the localization of arsenic in the 
animal economy. 
The most important feature of original work at the 
school of late years has been Dr. Bigelow’s introduction of 
the new operation of litholapaxy. 
A number of interesting papers have been recently 
written by members of the faculty, some of which contain 
new discoveries of considerable scientific importance. I 
cite two: “Effects of Certain Drugs in increasing or 
diminishing Red Blood-Corpuscles,” by Dr Cutter ; and 
“ Alterations in Spinal Cord in Hydrophobia,” by Dr. 
Fitz. 
The School of Agriculture and Horticulture, called “ The 
Bussey Institution,” is located on the sunny slopes of 
Forest Hills, about five miles southwest from Boston. The 
labors of the professors connected with this institution have 
been even more in the line of original research than of in- 
struction, though of late the lack of a sufficient endow- 
ment has interfered with the quality of work and the 
publication of the results. 
A number of exceedingly interesting and valuable 
papers, however, have appeared in the “ Bussey Bulletin,” 
the titles of which give some indication of the character of 
the work. I give a few of the more important : “ Hybridiza- 
of Lilies,” by Professor Parkman ; “ Diseases caused by 
Fungi” — Professor Farlow ; Examinations of Fodders,” 
“ Trials of Fertilizers,” “ Prominence of Carbonate of Lime 
in Soil-Water,” •“ Importance as Plant-Food of the Nitrogen 
in Vegetable Mold” — Professor F. H. Storer ; “The 
Potato-Rot,” and “ The Black Knot ” (of plum and cherry- 
trees) — Professor Farlow. — Popular Science Monthly. 
ON THE EFFECTS PRODUCED BY MIXING 
WHITE WITH COLORED LIGHT. 
It was noticed several years ago that when white light 
was mixed by the method of rotating discs with light of an 
ujrramarine (artificial) hue, the result was not what one 
^y/uld naturally have expected, viz. : instead of obtaining 
^lighter or paler tint of violet-blue the color inclined de- 
cidedly toward violet, passing, when much white was 
added, into a pale violet hue. Two attempts have been 
made to account for this curious fact : Briicke supposes 
that the light which we call white is really to a considera- 
ble extent red, and that the mixture of this reddish white 
light with the blue causes it to change to violet. Aubert, 
on the other hand, following a suggestion of Helmholtz, 
reaches the conclusion that violet is really only a lighter 
shade of ultramarine-blue. He starts with the assumption 
that we obtain our idea of blue mixed with white from the 
sky, which, according to him, is of a greenish-blue color. 
We then apply, as he thinks, this idea to the case of a blue 
which is not greenish, namely, to ultramarine-blue, and are 
surprised to find that the result is different. 
It will be shown in the present paper that these expla- 
nations are hardly correct, since they fail to account for the 
changes, which, according to my experiments, are produced 
in other colors by an admixture of white. I prepared a set 
of brilliantly colored circular discs which represented all 
the principal colors of the spectrum and also purple ; these 
discs were then successively combined in various propor- 
tions with a white disc and the effects of rapid rotation 
noted, a smaller duplicate colored disc uncombined with 
white being used for comparison. Under these circum- 
stances it was found that the addition of white produced 
the changes indicated in the following table : 
Vermilion became somewhat purplish. 
Orange became more red. 
Yellow became more orange. 
Greenish yellow was unchanged. 
Yellowish green became more green. 
Green became more blue-green. 
Cyan-blue became less greenish, more bluish. 
Cobalt-blue became more of a violet blue. 
Ultramarine (artificial) became more violet. 
Purple became less red, more violet. 
Exactly these same effects can be produced by mixing 
violet with the above mentioned colors. These experi- 
ments serve to explain the singular circumstance that when 
complementary colors are produced by the aid of polarized 
light, it is difficult or impossible to obtain a red which is 
entirely free from a purplish hue, a quantity of white light 
being always necessarily mingled with the colored light. 
In the case of the red, orange, yellow, ultramarine, and 
purple discs, I succeeded in measuring the amount of 
violet light which different proportions of the white disc 
virtually added to the mixture, and found that it is not di- 
rectly proportional to the amount of white light added, but 
increased in a slower ratio, which at present has not been 
accurately determined. 
For the explanation of the above mentioned phenomena, 
Briicke’s suggestion that white light contains a certain 
amount of un-neutralized red light is evidently inapplicable, 
since the effects are such as would be produced by adding 
a quantity not of red but of violet light, and for the present 
I am not disposed to assume that white light contains an 
excess of violet light. The explanation offered by Aubert 
does not undertake to account for the changes produced in 
colors other than ultramarine, and even in this case seems 
to me arbitrary ; neither have I succeeded in framing any 
explanation in accordance with the theory of Young and 
Helmholtz which seems plausible. — Prof. O. N. Rood, 
Ameiican Journal of Science 
BERNARDINITE : ITS NATURE AND ORIGIN. 
By J. M. Stillman. 
In a previous number of this Journal 1 I published the re- 
sults of a chemical investigation of a resinous substance from 
San Bernardino, sent to me by I Ion. B. B. Redding, which 
was said to occur in the form of vein in detached masses, 
and the vein to be traceable for three miles. The finders 
(farmers or “ ranchers ” of that vicinity) sent at the same 
time pieces of rock as vein-stuff which contained this pecu- 
liar resinous substance in the crevices. Some months later 
1 III 1 vol. xviii, p. 57 . 
