CORRESPONDENCE. 
223 
years before the year 1610, but certainly not before 1584. From 
the time of its discovery until about 1600 it remained compara¬ 
tively unknown. 
It is worth mentioning, however, that the first microscope, as 
is reported by Leibnitz, was brought from England to Cologne, 
in 1638, and not directly from Holland, the real cradle of micro¬ 
scopy. 
Perhaps, however, there may have been isolated cases where 
microscopical work was carried on in Germany. 
The fact is that the microscope first came into use, after the 
labors of Hooke, Malphigi, Leeuwenhoek, Schwammerdan, Ruysch 
and Grew were given to the world. The endeavors in the micro¬ 
scopical field remained very few, a circumstance which was caused 
by the defective construction of the microscope of that day, which 
gave no accurate results. 
As the discovery of the microscope was the absolute conditio 
sina que non for the origin of microscopy, even so, the perfection 
of the microscope, through the manufacture of aeromatic objec¬ 
tives, was the indispensable condition by which microscopy could 
be improved and perfected to an exact scientific discipline, so that 
the use of the microscope could be extended and applied to scien¬ 
tific research. 
Although the honor of the discovery of the microscope belongs 
to Holland, Germany and Holland shared the discovery of acro- 
matismus, through the labors of Van Deyl and Frawenhofer from 
1807-1811. The first era of microscopy begins with the manu¬ 
facture of aeromatic lenses. We must, therefore—for the history 
of microscopy in general, as well as its development in Germany 
—describe two periods, the first, from about the year 1600 until 
1811, that is from the discovery of the microscope, and the intro¬ 
duction of the microscope into Germany, to the first use of the 
aeromatic lens. The second period extends from 1811 to the 
present day. In both periods, the progress of microscopy is closely 
allied to the perfection of the microscope. In the examination of 
the steps in the development of microscopy, it is absolutely 
necessary to search for the first line in the development of the 
microscope. 
