38 THE AMERICAN MONTHLY [Feb 
Notes on Microscopy. 
M. I. CROSS. 
RETROSPECTIVE.—The year 1901 did not witness any 
startling development in connection with the microscope, 
but it was one in which avery steady progress was shown 
in nearly every department. It witnessed the introduc- 
tion of several new stands, principally for students’ use, 
two-speed fine adjustment devices, the increase in num- 
ber and variety, and, above all, in the aplanatism of sub- 
stage condensers and the substitution of actual working 
data for apprcximation in the case of tube lengths and 
. cones of illumination. In processes there were many 
new formule recorded, and judging from the number of 
articles which appeared on the subject, the science of 
micro-metallurgy is rapidly advancing. In the domain 
of preventive medicine, the best points of the microscope 
are becoming more fully appreciated and worked to 
greater advantage,and results are becoming increasingly 
reliable. In literature the fresh edition of Carpenter on 
the Microscope was a feature of importance, and the paper 
read by Mr. J. W. Gordon before the Royal Microscopi- 
cal Society in controversion of the Abbe theory of micro- 
scopic vision is still fresh in the memory. On the whole, 
microscopists can congratulate themselves on the work 
done in the past year. 
Co-OPERATION.—So much of the progress in microscopy 
in recent years has been attributable to the work of a 
few individuals that it has almost been lost sight of that 
the rank and file can and should do their share. It is 
eminently desirable that a column of this kind should be 
made the medium for conveying the thought, research 
and obstruction of microscopists generally. The subject 
is so many-sided that it is impossible for any one indi- 
vidual to present it in its various aspects, and it is for 
those who catch glimpses and side lights that others do 
