242 VETERINARY SURGICAL THERAPEUTICS, 
VIII. 
CUTANEOUS HORNS. 
Abnormal projections are sometimes observed on animals in various 
regions, but more particularly on the head. They are hard, formed of 
keratinized epidermic cells, and known as cudaneous horns. Generalized 
horns have, so far, been observed only in men. In animals—horses, cattle, 
sheep, dogs and cats—only cases of single horns have been recorded. Al- 
though their chosen spot is the head, they also grow on the back, flank, 
abdomen, and on the legs. They are of various lengths and sizes, straight 
or curved, smooth or rough. In parts exposed to repeated rubbings neo- 
formations similar to them maybe observed. (See Aygroma of the Knee.) 
Some of these productions fall off after several months, but are soon 
replaced by others. The others remain permanently. 
While in mammifera cutaneous horns are the expression of a horny 
hypersecretion due to causes which cannot be determined in some species 
of birds, especially in parrots, it is common to find on the cheeks or 
other regions of the head,.on the buccal mucous membrane, on the 
trunk and the extremities, horny productions of a tuberculous nature. 
Since attention has been drawn to these singular tuberculous neoformations 
we have met with several cases. In these the bacillus of Koch promotes 
the keratogenesis. Krampf has reported the case of a phthisical parrot 
which had on the right cheek a horn measuring two centimeters at its 
base and five centimeters in length. (See Fig. 56.) Megnin has recently 
reported a similar case. 
The only efficacious treatment is extirpation. If cutaneous horns are 
only sawed off they grow again. They must be removed entirely, and the 
portions of perverted skin where they are must be excised, or, as recom- 
mended by some, destroyed with caustics. The use of the bistoury is 
better. (For the treatment of cutaneous horns of the parrot, see Zuder- 
culosts.) 
The ichtyosis observed in calves by Numann, Gurlt, Pangoué, Goubaux, 
consists of a general hypertrophy of the epidermis. The skin resembles 
that of an alligator. There is no treatment for such an affection. All 
the calves which were affected with it died a few days after birth, 
