105 
at the present time, and he was inclined to think that in histo- 
logy, for the purpose of analysing organic structures, the existing 
microscopes were, as the Yankees would say, “ played out.” We 
have got as far as they will take us. He believed that a th did 
not enable anybody to see anything which could not be seen with 
a good ;,th of Ross. He considered these deep objectives to be 
eminently delusive, and they were so doubtless for the reasons 
which had been stated by Dr. Pigott. He could not doubt that 
Dr. Pigott had got on the right track of showing what was to be 
done in the present state of affairs. Practically the nature of 
the question just now is whether, in an organic tissue, one could 
truly define a point not more than =51,,,th of an inch in diameter. 
There was always that unhappy luminosity about the margins of 
such objects, which he did not doubt arose from the causes which 
Dr. Pigott had pointed out. Histologists, he feared, were at the 
end of their work unless, by the aid of some such appliance as 
Dr. Pigott had endeavoured to furnish, they could obtain micro- 
scopes which would enable them to separate two points the 
100,000th of an inch apart. Only then could they say whether 
the object was homogeneous or not. At present when they 
talked about homogeneous solids or fluids, or attempted to define 
an object like Bacterium, they were absolutely in cloudland. He 
had come to the meeting in the hope that he might hear that 
some light had been thrown upon this subject; and he did indeed 
trust that Dr. Pigott had proceeded some way on the road towards 
the solution of the difficulty; at any rate, he had macadamized 
the road, and that was a great matter. 
Dr. Pigott said he could well understand that so ardent a 
worker as Professor Huxley should feel the urgency of those 
wants to which he had referred. He thought, however, he might 
be allowed to say that in correcting the aberration of objectives, 
if there was nothing else to point to than a power of varying 
chromatic effects by means of the aplanatic searcher, a great im- 
provement would have been made. The object-glasses of the 
present year were greatly in advance of those of previous years 
as regards the correction of visible error which must therefore 
haye existed, however unsuspected and denied, for the very fact 
of their present superiority is a conclusive answer to the ques- 
tion as to whether any improvement had been made. 
Professor Huxley has published the following statement since 
the meeting: 
“T have had the great advantage of applying the ‘searcher’ 
to deep objectives under Dr. Royston-Pigott’s guidance, and I 
am disposed to form a very much more favorable opinion of its 
utility.” 
