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PROCEEDINGS OF THE SOCIETY. 
Meeting of 15th April, 1891, at 20, Hanover Square, W., 
the President (Dr. R. Braithwaite, F.L.S.) in the Chair. 
The Minutes of the meeting of 18th March last were read and 
confirmed, and were signed by the President. 
The List of Donations (exclusive of exchanges and reprints) received 
since the last meeting was submitted, and the thanks of the Society given 
to the donors. 
Cox, C. F., Protoplasm and Life. pp. 67. (8vo, New York, 1890) 
Slides (3) of sections of Teeth and Bone permeated with coloured ) 
collodion / 
Report and Proceedings, Ealing Microscopical Society .. . . j 
From 
The Author. 
Mr. T. Charters 
White. 
The Ealing Micro- 
scopical Society. 
The President said it would no doubt be remembered that at the last 
meeting, Mr. T. Charters White exhibited some specimens of sections of 
teeth permeated with collodion. He had now presented three slides to 
the cabinet of the Society, which would be valuable as illustrations of the 
results obtained by the process which he described in his paper. 
Prof. F. Jeffrey Bell, in reply to the President, said he had not yet read 
the book on c Protoplasm and Life,’ presented by Mr. C. F. Cox ; but he 
had — as he often did — opened it at the end, where his eye fell upon the 
words, “ Here I must leave the subject, lame and impotent though the 
conclusion may be.” He would take it home, and see if he could not 
get something better out of it than that. 
Mr. J. Mayall, junr M said there was also amongst the donations 
a copy of the Report and Proceedings of the Ealing Microscopical 
Society, which was worthy of notice, as it was not often that a society of 
so little pretension issued such an interesting abstract of its proceedings. 
Amongst other papers in the report there was one by Mr. Seebohm 
which had greatly interested him, and there were some others which he 
thought would also be found very well worth reading. 
The President read a letter from Mr. J. Aitken, of Falkirk, dated 
from Mentone, on “ A Spot Mirror Method of Illumination.” 
Mr. Mayall said the application of an opaque disc to block out more 
or less of the central portion of the mirror had long been known. In 
some of the Microscopes made in the last century by Dellebarre, the 
optician of Delft, Holland, there was a strip of brass 3 in. or 4 in. in 
length, with disc-like ends of different sizes, blackened or covered with 
cloth, made to slide under the stage in a spring-clip, and thus exclude 
the central light from the mirror, and give a more or less dark ground. 
Other methods had also been adopted by Dellebarre, one of which was to 
cement discs of black paper of different sizes on the under-faces of glass 
stage-plates. Central stops were very commonly applied to a disc of 
