102 Mr, Home’s Obfervations on 
found to have an uniform cuticular covering adhering to it, fimi- 
lar to that of the cutis on the furface of the body, from which 
it only differs in being thinner, and more delicate, bearing a 
greater refemblance to that which covers the lips. Others of 
this kind, inftead of having cuticle for their contents, are filled 
with hair mixed with a curdled iu bilance, or hair without any 
admixture whatever, and have a fimilar kind of hair growing upon 
their internal furface, which is likewife covered with a cuticle. 
Thefe cuticular incyfted tumors were, I believe, fir ft accurately 
examined by Mr. Hunter, to whom we are likewife indebted 
for an explanation of the mode in which the parts acquire this 
particular ftrudlure. 
Mr, Hunter confiders the internal furface of the cvft to 
be fo circumftanced refpefling the body, as to lofe the fti- 
mulus of being an internal part, and receive the fame im- 
prefiion from its contents, either from their nature, or the 
length of application, as the furface of the fkin does from its 
external fituation. "It therefore takes on actions fuited to fuch 
ffimuli, undergoes a change in its ftrudture, and acquires a dif- 
pofition fimilar to the cutis, and is confequently pofleffed of 
the power of producing cuticle and hair. What the mode of 
aftion is, by which this change is brought about, is not eafily 
determined; but from the indolence of thefe complaints, it 
moft probably requires a confiderable length of time to produce 
k„ That the lining of the cyft really does poflefs powers fimi- 
lar to cutis, is proved by the following circumftances : that it 
has a power of forming a fucceffion of cuticles like the com- 
mon fkin ; and what is thrown off in this w T ay is found in the 
cavity of the cyft. It has a fimilar power refpeSing hair, and 
fometimes the cavity is filled with it, fo great a quantity has 
been filed by the internal furface. Befides thefe circumftances, 
the 
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