JANUARY 11, 1901.] 
sembles temporarily the eye of a red-blind in- 
dividual. In like manner temporary green 
blindness and violet blindness may be produced 
by fatiguing the eye with light of the correspond- 
ingcolor. Very remarkable results are obtained 
when the eye is fatigued, not by exposure to 
one of the fundamental colors of the Young- 
Helmholtz theory, but by an intermediate 
color, such as yellow or blue. In case yellow 
light is used it is found that the persistence of 
vision is increased for both red and green: but 
that the persistence of vision for yellow light re- 
mains unchanged. The article contains much 
that is of great significance in connection with 
theories of color vision. In the same number 
of the Review, Dr. W. P. Boynton, of California, 
discusses the Gibb’s ‘Thermodynamic Model in 
the case of a substance obeying Van der Waal’s 
Equation’; while Dr. J. C. Shedd, of Colorado 
College, gives an analytical discussion of the 
various forms of curves that are presented by 
the fringes seen in the Michelson interferometer. 
SOCIETIES AND ACADEMIES. 
NEW YORK ACADEMY OF SCIENCES. 
SECTION OF BIOLOGY. 
THE regular monthly meeting for December 
was held on the evening of the 10th, Professor 
C. L. Bristol presiding. 
Professor Lloyd offered his resignation as 
Secretary of the Section, on account of his in- 
tended absence in Europe. On the motion of 
Professor Wilson, seconded by Dr. Calkins, a 
vote of thanks was tendered to the Secretary 
for his interest in furthering the work of the 
Section. 
The following program then was offered: 
G. N. Calkins: ‘Some interesting Protozoa 
from Van Cortlandt Park.’ 
H. HE. Crampton: ‘Elimination in Lepidop- 
tera.’ 
E. B. Wilson: ‘The Chemical Fertilization 
of the Sea Urchin Egg.’ 
Dr. Calkins stated that there were fonr 
genera of Protozoa which are usually regarded 
as intermediate forms between the classes of 
Protozoa were considered. These were: Nu- 
clearia, intermediate between the Rhizopoda 
and the Heliozoa; Mastigamoeba, intermediate 
SCIENCE. al 
between Mastigophora and the Rhizopoda; 
Multicilia, intermediate between the Mastigo- 
phora and Ciliata, and Actinobolus, intermediate 
between the Ciliata and the Suctoria. The 
method of feeding in the latter form was also 
described for the first time. All these forms, 
together with 54 other genera and a great 
many species (100 to 150) were found in the 
waters of Van Cortlandt Park during the past 
fall. 
The paper by Dr. Crampton was designed to 
be the first of a series dealing with the problems 
of variation and selection in Lepidoptera, and 
especially in the Saturnid moths. The par- 
ticular questions here considered are as to the 
relative variability of eliminated and surviving 
pup and moths of Philosamia cynthia, and as 
to the relative variability of males and females. 
From a lot of 1,090 cocoons from a restricted 
locality, 310 living and 632 dead pupz were 
obtained, the remainder being shriveled or 
abnormal larve and pups. The living pups 
were compared with an equal number of dead 
pupee in reference to certain body-characters 
(length, length of bust, width, depth, frontal 
stature and sagittal stature of bust), and to 
certain characters of a typical organ, the left 
antenna (length, breadth and stature). It ap- 
pears that the surviving males are slightly less 
variable than the eliminated males, and that 
the surviving females are far less variable. 
From the living pupz 180 perfect moths were 
obtained. The males were from pupz which 
were far less variable than pupz producing ab- 
normal moths; but the females were from rela- 
tively more variable pupz, though the latter 
were much less variable than eliminated female 
pupe of the preceding group. The paper will 
be published in full. 
Professor Wilson presented the results of a 
study of the phenomena of development in the 
unfertilized eggs of Toxopneustes when treated 
with solutions of magnesium chloride by Loeb’s 
method. The results confirm Loeb’s conclusion 
that the embryos arising from these eggs are 
produced without fertilization by spermatozoa, 
conclusive proof being given in the fact that 
during cleavage the number of chromosomes 
is half the usual number, namely 18 instead of 
36. The mitotic phenomena differ in many de- 
