32 
The President's Address. 
Lieberkuhn illumination^ and tlie instrument was exhibited. 
It affords ready means of bringing into view any part of the 
object under examination : it has many advantages over the 
usual forceps attached to the stage, for which it is a con- 
venient substitute. The author states that, by the use of 
this little instrument, he has ascertained many facts which 
he never could satisfactorily determine before.^^ 
A. 3. A paper On Cleaning and Preparing Diatoms/^ by 
J. A. Tulk/^ communicated by Dr. Millar, was read 
October 8th., published 'Trans. Mic. Soc.,' vol. xi, N. S., 
p. 4. 
The author gives directions for collecting the diatoms, so 
that from the first the gathering may be as free as possible 
from foreign admixture. He then explains how all inpurities 
unavoidably present may be removed. Finally, he gives full 
details of the manner of mounting the prepared specimens 
either in Canada balsam, or in the dry way. Many a micro- 
scopist, without doubt, will gratefully acknowledge his obli- 
gations to the author for these practical hints. 
At our last meeting, when there was no paper, the Rev. 
J. B. Reade communicated a method of separating Desmidise, 
which he had practised with great success. It consists in 
taking advantage of the endowments of the living organisms, 
whence it results that they become firmly attached to ap- 
propriate surfaces, while any impurities that may be mixed 
with them may be readily diffused through the water which 
contains them. 
Putting the gathering into a wide shallow vessel, as a 
common soup plate, and covering it completely with water, 
the whole is set aside for ten or twelve hours, by which time 
the living organisms will have become fixed to the surface of 
the plate; then, by slightly tilting the plate, and gently 
agitating the water, the foreign substances will be diffused 
through the liquid, and by pouring off the water, will be re- 
moved with it ; this may be repeated, if necessary, without 
detaching the Desmids. Finally, having added a little clean 
water, the Desmids may be gently separated and easily trans- 
ferred to the receiving bottle perfectly clean and free from 
all foreign matter. 
Two papers were read " On the Application of Photography 
to the representation of Microscopic Objects as seen through 
the Microscope.^^ 
4. The first of these, On Micro- Stereography,^^ by Mr. 
J. Smith, was read May 14th. 
The plan adopted by the author to obtain match pictures 
was to cover in succession the right and left half of the 
