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of Botany, Zoology, Geology, Ac., progress, there arises an increasing 
tendency to what is known as specialisation. And thus it comes to 
pass that many original biological investigations, which not very long 
ago would have been discussed before our Society and recorded in our 
columns, now find their way to the Proceedings of other Societies 
which division of labour has called into existence in recent years, and 
this notwithstanding the fact that the true solution of the problems 
involved frequently depends on critical examinations with the widest 
apertures and the most perfect appliances of modern Microscopy. If 
this Society is to live a vigorous life an improvement must take place 
in this respect ; let me therefore urge that those F ellows who are 
doing original microscopic work will contribute at least some of their 
papers to this Society. 
Finally, the thanks of the Society are due to our Assistant-Secretary 
Mr. Parsons, who assumed office at a period of exceptional difficulty, 
and who has fulfilled his duties entirely to the satisfaction of your 
Council. This concludes what may be called the official part of my 
address, which relates to the work of the Council as well as to the 
management and control of the Society ; but before beginning the 
second part let me say a few words on the changes that have taken 
place among our staff of officers in the course of the year just closed. 
Prof. Bell, who has been an abstractor for the Journal for the last 
eighteen years, one of our Secretaries for fifteen, and our Editor for 
seven years, has now resigned these posts. During these years the 
zoological abstract has been conducted with such marked ability as to 
have elicited commendation, not only in this country, but abroad. The 
Society has already becomingly expressed its thanks to him for his 
valuable services in these several capacities during such an extended 
period, and I feel sure the Fellows will most willingly accord their 
tribute of appreciation of the work he has done. 
Considerable activity has been displayed in the department of 
Microscopy during the past year. First, with regard to the theory of 
the Microscope, there has been another contribution to the literature 
of the cf Abbe theory,” by the President of the American Microscopi- 
cal Society, Dr. A. Clifford Mercer, who is a Fellow of this Society, 
and well known to many of us. The pamphlet, which consists of 
7 6 pages, 35 photos, and several woodcuts, is entitled ‘ An Experi- 
mental Study of Aperture as a factor in Microscopic Vision.’ In it 
the author combats the Abbe idea of microscopic vision being a thing 
sui generis, and regards the laws of undulatory light, as already enun- 
ciated for the telescope and photographic camera, as applicable to the 
Microscope; he utterly condemns the narrow cone and oblique light, 
and considers the 3/4 axial cone as the most suitable method for 
Microscope illumination, and bases his resolving limit accordingly. 
iSorne important experiments are described which demonstrate the 
correctness of Lord Bayleigh’s limit of resolution for circular apertures 
.as contrasted with that calculated by Sir George Airy. With regard 
