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ON THE PRODUCTION OF HAIR ON THE 
arc mostly found where there are collections of mucous follicles. 
It is rare that several crypts or follicles are not found where the 
hairs are longer than usual; and almost always, round the central 
longest hair, there are many other smaller ones taking a parallel 
direction. I have never found an intestinal hair, even among the 
largest of them, whose bulb was situated either in the submucous 
cellular tissue, or on the muscular tissue. 
It is difficult always to seethe exact direction of the free por- 
tion of the hair. It is probable that the mucus would keep them 
straight, or perpendicular to the surface in which they are planted ; 
but they yield occasionally to the pressure of the aliment, and 
they bend in the direction which the aliment and the mucus take 
within the intestine. 
As to their chemical properties, it is impossible to ascertain 
them, because a sufficient number could not be obtained. M. 
Lassaigne says, that nitric acid turns them yellow — that they 
are soluble in weak potash, and that while burning they diffuse 
a strong empyreumatic odour, like those of the skin. 
In those parts of the intestinal mucus in which they are 
found, they are not planted in a uniform manner. Sometimes 
thousands of them are collected together round the pylorus, whe- 
ther in the stomach or intestine ; at other times they are distant 
half a line, or a line from each other. At the curvatures of the 
colon they are more numerous in some horses than in others. 
In the csecum they are most thinly, and yet regularly, scattered. 
Sometimes there are not more than one or two in the space of a 
square inch. In addition to this, their distribution varies consi- 
derably in different animals. 
Such is the result of my researches as to the existence of hair 
in the gastro-intestinal mucous membrane of the horse. 
Do they exist in other animals ? I have searched in vain for 
them on the mucous membrane of the intestines of the sheep ; 
but I once found them in the fourth stomach of the goat. 
I have been more fortunate in my researches in the ox. I have 
three or four times found them in the abomasum of the ox, and 
twice as numerous as in the stomach of the horse. They were 
most numerous on the summits of the rugse, and especially 
towards the pyloric orifice, than around the esophagean entrance. 
The colour was the same as that of the coat of the animal, and 
some of them appeared used and roughened at their free ex- 
tremity. I have not found any in the intestines of these animals, 
nor, indeed, on any other part of the mucous membrane than 
the abomasum. 
After considerable research, I am inclined to believe that they 
are not perceivable on the intestinal mucous membrane of the 
