126 The Ciliary Muscle and eee om 
which arise from the thick end of the “ note of admiration” mark- 
ings being the last to transmit the light, showing that these are 
real prominences. 
With respect to the “Aplanatic Searcher,” it would be unfair 
to Dr. Pigott to discuss its merits, till we have a description before 
us of its construction and use, so that we can adapt and try it in 
the same form. I am glad that the optical principle and correction 
of the objective-glass is now brought prominently forward, and the 
effects of spherical aberration investigated. I may, however, remark 
that in the adjusting glasses, as sent out by our best makers, the 
effects of posttive spherical aberration only can be observed, as some 
range of this is given by the closing of the lenses for the purpose 
of balancing the negative error produced by glass of different thick- 
nesses. In order to observe the effect of negative spherical aberration 
on a globule, the index tongue must be taken off the mount, so that 
the glasses can be separated beyond the range to which they were 
limited by the maker. ‘This is the neutral point between the two 
errors, where all aberrant rays are brought to one exact plane, the 
APLANATIC FOCUS of Mr. Lister. 
IIlI.—The Ciliary Muscle and Crystalline Lens in Man. 
By J. W. Huss, F.R.C.S8., F.R.S.* 
In the course of lectures ‘‘On the Minute Anatomy of the Eye” 
which I had the honour of delivering before the College of Surgeons 
last summer, and which were published in this Journal, I described 
the histology of the cornea and vitreous humour, of the retina and 
tunica uvea. 
‘There remain the parts concerned in the accommodation of the 
eye, and the conjunctiva, sclerotic and optic nerve, an account of 
which will complete the normal anatomy of the eye-ball. 
I propose to devote the present lecture to the apparatus of 
accommodation. 
Let me in the first place endeavour to explain what the term 
accommodation technically means. 
That we cannot see perfectly distinctly at the same instant two 
objects placed at different distances before the eye is a fact of the 
truth of which a moment’s attention suffices to convince the most 
unobservant person. The fact is most easily realized when the 
objects are near, for when they lie at a great distance from the 
spectator the minor distinctness of one of them is less appreciable, 
but when they are relatively close to the spectator it is umpossible 
* Being the first of the Aris and Gale Lectures delivered during the present 
year at the Royal College of Surgeons. 
