PROCEEDINGS OF SOCIETIES. 229 
it cannot be easily distinguished from muscles of ordinary 
elastic tissue, but it is open for any one to say that they are the 
ends of real muscular fibres. It is, therefore, necessary to resort 
to other specimens; and in birds we find that the muscle is 
striated and beautifully striped, so that in them there is no 
mistake, and it cannot be taken for anything but what itis. I 
have made a number of sections, of which I present a series here 
to-night, to verity these my statements. By tinting with carmine, 
it is perfectly easy to see where there is muscular fibre, and 
amongst the whole of the specimens examined there is not one 
which contains a single circular or sphinctral muscular fibre. It 
is open to say that the muscle of a fowl is not arranged in a way 
similar to that of man, but if we find that in birds there 
absolutely is nothing of the kind, and in man there is only that 
which can be even guessed at, it therefore appears as if the thing 
had but an imaginary existence. If, however, in this way we 
throw doubt upon that accepted theory of the effect upon the 
lens, of the circular fibres of the ciliary muscle, if this be a true 
objection—and it is one merely destructive of fact without giving 
us in its place a constructive theory—the matter is not left where 
we should wish to leave it. In the bird nothing can be more 
clear than that the fibres of this muscle pass into the cornea 
from the sclerotica, and that they terminate in the cornea almost 
en masse. I have here some specimens in which the whole ring 
of muscular fibres is shown to terminate in the cornea, and I 
have also some drawings made by Mr. Ruffle from the prepara- 
tion, showing what he saw; and although he shows only one part 
of the truth, he shows just that very portion that I am pointing 
out now. As he saw it, the whole of this anterior portion is 
inserted into a ring surrounding the cornea. Well, then, you 
see if you have in the bird a great mass of muscular fibre, passing 
from the sclerotic into the cornea, you get at once a hint that the 
old physical theory (that which was replaced by this theory under 
consideration), that the curvature of the cornea was changed, gets 
some support. Helmholtz says that he can detect no change in the 
shape of the cornea, and in the face of this lam not going to set up 
any theory. Some time ago I took out the eye of an ostrich, for 
disease—one of the ostriches at the Zoological Gardens—and I gave 
it to Dr. Lawson, who published a paper on it in the ‘ Popular Sci- 
ence Review,’ showing the corneal insertion of the muscle. But 
leaving the optical part of the subject, I wish to say that by con- 
tinuing inquiries as to the structure of the iris in birds, seals, 
and creatures which see both above and under water, and in whose 
case great power of adaptation is possessed in order to enable 
them to see in different media, there is ground for believing that 
great alteration may be made in the present theory of accom- 
modation simply by microscopic research. In the whole of the 
bird tribe this circular ciliary muscle is entirely absent, and in 
the case of oxen, pigs, and in man, there is, I hold, no proof what- 
ever of the existence of a sphincter muscle either. Whilst carry- 
