OR, A TREATISE ON- PILE. 9] 
which (hair) was of a bright d/we color, owing to its having taken up some of the coloring 
matter used in the tattoomg. We have repeatedly tried to inject a hair, but have never 
succeeded. Again, a woman, about thirty, became enciente, and at the seventh month, 
her skin of the face first assumed the color of oxide of iron; and afterwards it became 
black. On some days it was of a deeper shade than on others ; her hair was naturally black, 
but it assumed a darker shade, The black of her face disappeared two days after her 
accouchement. Besides, Keidline mentions a case where the hair became bright yellow 
during a fit of jaundice ; but he does not mention the original color, and Alibert tells of a 
blonde-haired woman whose hair became black after a severe accouchement. (See Dict. des 
Sci. Med., v. 43, p. 273.) A still more extraordinary case is mentioned in p. 503, of the 
same work, of a female whose hair, shortly before her death by consumption, changing 
from white to black.* The hair which is rubbed from the hides of horses with colored 
pile, sometimes is succeeded by white hairs, and sometimes, (though less frequently,) by 
hair of the original color. 
When a wound heals “ by the first intention,” the original skin closing and joining, 
hair grows and continues of the same color it was originally; but when it heals “by 
granulation,” a new and imperfect skin is formed, with a very white hue and smooth surface, 
’ 
and upon thisno hair willgrow. Feeding an animal for some time upon madder turns the bones 
red, but it has no effect upon the hair. Dr. Belchier, an English physician, from seeing a pig 
which had been fed at a dyeing establishment have reddish colored bones, first discovered 
the phenomenon. He repeated the experiment upon other animals, and always with the 
same result. 
Or THE PoLaRrizaTION oF Ligut By PitE.—Hairs polarize light. (Mandl, 'Traité. Prac. 
du Microscope, p. 165.) Common light originates in vibratory motions in every direction 
transverse to the ray; but polarized light is caused by vibrations, transverse to the ray, 
and in one direction only. The part of the hair which is instrumental in producing this 
phenomenon is, probably, the cortex, which is scaly. Polarization may be caused by 
reflection, refraction or double refraction.+ 
In viewing hairs under the microscope, we must remember the shape of the hair, for 
light impinging on its surface, being reflected according to the angle of incidence, will be 
reflected differently as the hair is cylindrical, oval or flat. We should also recollect that 
the rays of light which emanate from the reflector of the microscope, situated beyond or 
beneath the hair, being of different lengths, will cause a series of light and dark colored 
stripes and shadows, which, unless properly understood, will cause false impressions of 
the object. 
And, lastly, the rays of light, striking directly upon the hair, and those reflected by the 
reflector, which is beyond or below the object, may interfere and nullify each other. This 
danger is increased when two reflectors, one above and one below the object, are used. 
* May this not have been a falling out of the old colorless hair, and its place being supplied by new black ones? 
+ The shadow lines of light upon hairs, which, owing to their minuteness, are invisible to the naked eye, become colored 
under the microscope, 
23 
