20 
collection contains specimens from Chester, 
England (Newstead); and on the white oak 
from Stettin, Prussia (Pergande). 
Aspidiotus spurcatus has been reported from 
France and Italy on poplar and Platanus. 
It will be noted that the Department and 
other records exhibit not only a wide range 
of food plants, but a very extended distri- 
bution in Europe, both geographically and 
as to climate. This scale insect, therefore, 
seems to be one well worthy of attention 
and one that will bear watching. It is to 
be hoped that it will not be as disastrous to 
our fruit interests as have been other for- 
eign scale insects imported to our shores. 
C. L. Maruarr. 
U. S. DEPARTMENT OF AGRICULTURE. 
Nore: After returning the proof of the above to 
SCIENCE, part of the type material of a supposed new 
species of Aspidiotus (A. hunteri), found in 1897 on 
currant at Alton, Iowa, was sent to this department 
by the describer of the species, Mr. Wilmon Newell, 
Assistant Station Entomologist, Iowa Experiment 
Station. The material in question proves to belong 
to ostreeformis, and is very interesting as showing the 
occurrence of this species so far west and also as in- 
dicating a new food plant. 
CROSS-EDUCATION. 
Tue term ‘cross-education’ is used to 
express the theory that the effects of prac- 
tice on one side of the body are transferred 
to the unpracticed side. The subject has 
been investigated during the past year at 
the Yale Psychological Laboratory in the 
effort definitely to establish the fact of 
transference of practice and to arrive at an 
explanation of the causes of such transfer- 
ence. Following is a brief summary of the 
experiments carried on and the results ob- 
tained from them: 
a. Rapidity of voluntary effort.—A  tap- 
counter was constructed from clock-work 
and connected electrically with a telegraph 
key. Ateach pressure of the key by the 
hand or the foot the counter registered one 
tap. Records of maximum rapidity of tap- 
SCIENCE. 
[N.S. Vou. X. No. 236. 
ping were taken for right and left index 
fingers and right and left great toes sepa- 
rately. Then for two weeks the right great 
toe alone was practiced in tapping daily for 
a considerable time. Then all four digits 
were tested as at the start. The result for 
six subjects showed that the average rela- © 
tive gain for the right great toe~-the mem- 
ber practiced—was 31% ; for the left great 
toe, 30% ; for the right index finger, 20%; 
for the left index finger, 28%. The last 
three had, therefore, gained by practice of 
the first. 
b. Strength of voluntary effort.—Six subjects 
were tested as to the number of times they 
could raise a dumb-bell weighing 2} kilos 
(5 lbs.). Girth measurements of the right 
and left arms were taken and the dyna- 
mometric pressure of each hand was de- 
termined. For two weeks the right arm 
alone was exercised in raising the dumb- 
bell. Results: (1) The average gain of the 
right arm in the number of flexions made 
was 470%; of the left arm, 150%. (2) The 
average gain in the girth of the right 
biceps was 64 mm.; of the left biceps, 22 
mm.; of the right forearm, 42 mm., and 
of the left forearm, 24mm. (3) The aver- 
age dynamometric pressure increased in the 
right hand 13%, in the left 13%. (4) Prac- 
tice of the right arm inured both arms to 
resist the after-effects of violent exercise as 
revealed by stiffness, pain and soreness. 
These experiments proved not only the fact 
of cross-education in ability to do work, but 
also the fact of cross-development, in a 
lesser degree, of the symmetrical muscles. 
c. Accuracy of voluntary effort—A target 
was so devised that permanent records of 
accuracy in lunging with a fencer’s foil 
could be obtained. Records of both right 
and left hands were secured with six sub- 
jects. The lunging was then practiced for 
two weeks with the right hand only. There- 
after both hands were tested. Results : 
(1) Both hands had gained in accuracy, 
