418 
PROCEEDINGS OF THE SOCIETY. 
window, tliere would be no difficulty in following any desired rotifer. 
He should, perhaps, want one not more than a quarter of the size of that 
upon the table, though no doubt for the purpose originally intended it 
was all that could be desired. 
Dr. Dallinger said he had one made for his own use of a size suitable 
for the X 10 magnifying power. He also found it to be an advantage 
to fit it upon a wooden mount provided with a winch, by means of which 
it could be raised or lowered as convenience required. 
The President said that Mr. Eousselet had used with advantage a 
piece of black cloth or board on the other side of the tank, so as to 
obtain a black background, on which the rotifers were seen bright. 
Prof. M. Hartog’s paper “ On the State in which Water exists in 
Live Protoplasm,'’ was read by Prof. Bell, who explained that it was 
brought before the British Association at their last meeting, but had not 
been printed. 
The thanks of the Society were given to the author. 
Mr. E. M. Nelson said that Mr. Halford had been experimenting in 
the matter of mounting the spermatozoa of the Salmonidse, obtained from 
the milts of spawning fish ; but the results were not satisfactory. This 
year, however, he had mounted them in another way, and the result had 
been that details which had formerly been invisible with the highest 
powers, could now be seen with a 1 in. A paper descriptive of the 
method adopted was then read to the meeting, and specimens in 
illustration were exhibited by the lantern upon the screen. (See ante, 
p. 404.) 
Mr. Mayall thought it would be well to mention that the gathering 
which was to have taken place this year at Antwerp in celebration of 
the 300th anniversary of the invention of the Microscope, had been 
unavoidably postponed until next year, in consequence of some difficulties 
which had been met with in getting ready the premises in which the 
meetings were to be held within the time at disposal. 
Mr. E. M. Nelson then exhibited on the screen several slides showing 
under high powers ( x 1350) the bordered pits of Pinus sylvestris, also 
radial structure in Pinus and Tilia. He also exhibited a small series of 
slides to show the qualities of a new apochromatic 1/4 in. objective, with 
fluorite lenses, and of • 95 N. A., one of a series of new apochromatic objec- 
tives recently jjroduced by Messrs. Powell and Lealand. (Objects 
shown : — “ Secondary ” structure of Isthmia enervis ; P. angulatum^ with 
dry 1/4 in. ; same diatom on dark ground, with 1 in. ; same, wdth apochro- 
matic oil- immersion 1/8 in.; fracture through “secondary” marking of 
Triceratium favus ; “ postage-stamp ” fracture on P. angulatum ; black 
dot on P. angulatum^ with 1/4 in., x 600 ; same, with 1/2 in., showing 
white dot only.) 
Mr. Bennett inquired, with regard to the bordered pits of the pine, 
whether Mr. Nelson was quite satisfied as to the existence of the 
membrane in the mature as well as the young structure, because it 
