VOL. LXXXI.] PHILOSOPHICAL TRANSACTIONS. 31 



inches in circumference at the base, or thickest part. This woman, named 

 French, who lived near Tenterden, had a tumor or wen on her head, which in- 

 creased to the size of a walnut; and in the 48th year of her age this horn began 

 to grow, and in 4 years arrived at its present size*. 



There are many similar histories of these horny excrescences in tlie authors 

 above quoted, and in several others; but those mentioned above are the most 

 accurate and particular with respect to their growth, and in all of them we find 

 the origin was from a tumour, as in the 2 cases first related; and though the 

 nature of the tumour is not particularly mentioned, there can be no doubt of 

 its being of the incysted kind, since in its progress it exactly resembled them, 

 remaining stationary for a long time, and then coming forwards to the skin; and 

 the horn being much smaller than the tumour before the formation of the horn, 

 is a proof that the tumour must have burst, and discharged its contents. 



From the foregoing account it must appear evident, that these horny excres- 

 cences are not to be ranked among the appearances called lusus naturae: nor are 

 they altogether the product of disease, though doubtless the consequence of a 

 local disease having previously existed; they are, more properly speaking, the 

 result of certain operations in the part for its own restoration; but the actions of 

 the animal economy being unable to bring them back to their original state, this 

 species of excrescence is formed as a substitute for the natural cuticular covering. 

 To explain the manner in which these horns are formed, it will be necessary to 

 consider the nature of incysted tumours a little more fully; and in doing so we 

 shall lind, that this particular species does not differ in its principle, nor mate- 

 rially in its effects, from many otliers which are not uncommonly met with in 

 the human body, as well as in those of many other animals, which, as they are 

 more frequent in their occurrence, are also much better understood. 



Incysted tumors differ exceedingly among themselves, both in the nature of 

 their contents, and in their progress towards the external surface of the body. 

 Many of them have no reference to our present purpose; it is only the more in- 

 dolent kind to which it is meant now to advert: some of these, when examined, 

 are not found to contain a fluid, but a small quantity of thick, curd-like matter, 

 mixed with cuticle broken down into small parts, and on exposing the internal 

 surface of the cyst, it is found to have a uniform cuticular covering adhering to 

 it, similar to that of the cutis on the surface of the body, from which it only 

 differs in being thinner, and more delicate, bearing a greater resemblance to 

 that which covers the lips. Others of this kind, instead of having cuticle for 



* The following extract is taken from the minutes of the u. s., Feb. 14, 1704-5. " A letter 

 was read from Dr. Charriare, at Barnstaple, concerning a horn , 7 inches long, cut off the Qd ver- 

 tebra of the neck of a woman in that neighbourhood. Dr. Gregory said, that one of 7 inches long, 

 and of a dark brown colour, was cut off from a woman's temple at Edinburgh. Dr. Norris said, that 

 2 horns liad been cut off from a woman's head in Cheshire." — Orig. 



