i88o.J 
Notes. 
733 
under the red and green lights, though retarded, was effeaed in 
perfeaion. 
We learn that the Rev. W. H; Dallinger, of Liverpool, the 
distinguished microscopist, has accepted the appointment o 
Governor and Professor of Biology at Wesley College, Sheffield. 
This institution may he congratulated on the acquisition it has 
made. 
We learn with regret that' the robin-redbreast is eaten in 
Loraine in such numbers that they are becoming scarce. What 
is still worse, we hear that a certain French provincial prefet has 
given orders for the destruction of swallows and martins as 
injurious ! 
One George Aldersbury, an imitator of Dr. Tanner, has suc- 
cumbed to the system of fasting which he had attempted. 
According to‘ the Berlin “ Klinisches Wochenblatt ” hasmo- 
globinuria may be caused by inhaling hydrogen arsenide, even in 
small proportions, — e.g., hydrogen gap prepared with sulphuric 
acid and zinc contaminated with arsenic, as is often the case. 
The “ Medical Press and Circular ” states that Mr. Malcolm 
Morris, Honorary Secretary of the London Medical Society, is 
issuing circulars requesting Fellows of the Society who have 
seen ?ases of arsenical poisoning by means of wall-papers to 
forward particulars to him at 63, Montague Square. 
A paper “ On the Function of Aperture in Macroscopic 
Vision,” by Prof. Abbe, of Jena, has come before the Royal Mi- 
croscopical Society. As the paper would occupy about 150 pages 
of the Journal, the Council have decided to print it as a separate 
volume. 
Dr. H. Stolterforth, M.A., in a communication to the Quekett 
Club recommends boiling in soap and water as a means of 
cleaning Diatomaceous materials, in all cases where it is avail- 
able, in preference to the ordinary mode of treatment with acids 
and strong alkaline solutions. He considers it far less liable to 
do mischief to the delicate organic structures under treatment 
than the ordinary methods. 
In a paper read before the Royal Microscopical Society, Mr. 
T w Stephenson demonstrated that the visibility of minute 
obiedis depended upon the difference between the refradtive 
index of the medium in which they were viewed and that ot the 
objedts themselves, and, further, that it was useless to employ 
objectives of the large apertures now attainable unless the 
ob edts were mounted in media capable of utilising the whole of 
laro-e pencil; by using them on objefts mounted in air their 
effedtiveness is reduced to the common level of i8o°=i - o nume- 
rical aperture. The following table of indices is given . • 
