Presidential Address. By A. D. Michael. 101 
tomy and research are daily becoming greater, and notwithstanding 
the immense assistance obtained from section-cutting it continually 
becomes more and more important to work upon very minute objects 
under a Microscope. To meet these requirements there should be 
objectives of half-inch focus, under which a knife or other instrument 
can be freely used ; but how few there are, and they are rather 
diminishing than increasing ; it is true that they would not probably 
give the definition which is obtained by objectives which have less 
working-distance, but there is ample field for both ; and a serious 
effort should in my opinion be made to produce half-inch objectives 
with more working distance than is possessed by most of those at 
present supplied, combined with the best possible definition which can 
be obtained at that distance. The effort should not cease here ; 
human skill persistently directed to a desired object does many things, 
and I trust that the time may come when we may be able to dissect 
under higher powers than a half-inch. It is true that apochromatic 
lenses and compensating eye-pieces have done a good deal for us in 
this connection ; for they have enabled us to use deeper eye-pieces, 
and consequently lower objectives, to obtain the same amplification ; 
but these eye-pieces, excellent as they are, have some disadvantages, 
among which is not being very suitable for the Stephenson binocular, 
which is, in my opinion, still facile 'princess among dissecting instru- 
ments. 
The next point is one which I have mentioned before from this 
chair ; namely that in these days when section-cutting is one of the 
greatest, if not absolutely the greatest, means of biological research, 
and when we are anxious as far as possible to mount a whole series 
of sections on one slide, it is most desirable to have a good mecha- 
nical stage that has a motion of 3 in. by 1 in., or very close to 
that measurement. Only those who themselves use serial sections to 
discover what was previously unknown can thoroughly grasp the 
importance of this ; serial sections are not a book which everyone who 
runs may read ; in minute and complicated anatomy the information 
is there, but it is written in a language which it requires the closest 
attention to understand ; the eye and the mind have to follow the 
individual organ which is being traced from section to section, often 
through a great number of sections, and preserve clearly in the 
mental vision the result of the combination of these numerous and 
varying pictures. The continual shifting from row to row of sec- 
tions, or worse still from slide to slide, distracts the attention, and 
interferes seriously with the powers of realising the results ; therefore 
the longest mechanical movement of the stage is of substantial impor- 
tance ; and it is equally important that whatever movement there is 
shall be capable of being exerted without bringing any part of the 
apparatus up against the substage condenser and upsetting that. 
Since I called attention to this subject before, two very ingenious 
arrangements have been brought forward with a view to remedy the 
