Mr. Home's Lecture 
18 
the length of time the muscles have been left to themselves; 
for it is with difficulty they acquire an increased degree of 
action after having been long habituated to a more limited 
contraction. 
Of the Nature of the Cornea , some of its Diseases , and Mode of 
Treat?nent. 
The cornea of the eye, as the name implies, has been con- 
sidered of a cuticular nature. Baron Haller compares it to 
the nails in a soft state, and believes that in its regeneration it 
resembles the epidermis. 
This opinion is founded upon its want of sensibility, and 
having no vessels which carry red blood; the appearance it 
puts on when preserved in spirits, which is exactly similar to 
the nails at their roots, probably confirmed this supposition. 
As the cuticle is devoid of life, it is only under the influence 
of disease during its growth; once formed, it continues un- 
changed. The cornea, were it of the same nature, would be 
equally incapable of taking on new actions from disease, or 
any other cause ; but we find, on the contrary, that it under- 
goes many changes, which exactly correspond with those which 
the living parts of an animal body go through when under the 
influence of disease, from which I am induced to consider it 
alive; and I find that many of the present teachers of anatomy 
are of the same opinion. 
To prove that the cornea has life it is necessary, as a previous 
step, to shew, that being supplied with vessels which carry red 
blood, and having sensibility, are not essential to the possession 
of the living principle; for this purpose all that is required is to 
