Sent from Edward Nettleship
19 Sep 1911
Description:

‘My dear Pearson - Yours of 14^th.

 

Ordinary, normal, pigmented hairs contain both granular & diffuse pigment? Your position is, if I am right, that the essence of albinism is absence of the granular form; that however much macroscopic, fixed, colour a hair (or skin) may show, the bearer is essentially an albino if the pigment is of the diffuse kind; and that, as a logical conclusion total absence of all pigment – diffuse as well as granular – does not make the individual a less [sic] perfect albino than another whose hair (or) skin are diffuse-pigmented.

I suppose there would be some sort of rider to the effect that, as at present advised, diffuse pigmentation could not reach more than a certain (perhaps yet undetermined) intensity, so that a really black albino (from diffuse black pigment) shd. not be expected, i.e. that great depth of shade, or any shade of certain tints, means granules.

The spectacle mark we have (a) dirt, (b) effect of tears & mucus in gumming the hairs together & so making them look darker than when dry & separate from each other, (c) pigment within the hairs, presumably granular & diffuse in most coloured Pekes (face & espec. spectacle region is usually the darkest part of the coat of Pekes that are not black), & presumably (or proved by Scott[?] or you) diffuse only inthe albinos.

Obviously (a) & (b) will vary with external conditions in same dog. And it seems clear that (c) varies too according to either exposure to sun & wind (but this is difficult to separate from (a) & (b) wh. vary with the same conditions), or physiological states e.g. sexual influences in ♀. The “control” wd. be to keep both ♀ & ♂ in dark clean confinement for long period, - very difficult to carry out for any of us.

I gather that you cannot remove all the colour from spectacle mark hairs, by alcohol process. Is the same true for the “fawn” &c coloured hairs of body of albinos, or has material been too small to test this?

The skin I mention with spectacle mark resistance to washing is pom Fi. ob. About 6 months old; the mark is small but characteristic, I am not sure whether you had some of the hairs; anyway you can have the skin to do what you like with it if you say the word. It is “cured” & that may affect the solubility &c. of the pigment? It has not be[en] done with alcohol, unless alcohol comes into the “curing” process (unlikely). I have the instructions how to, from you, but never got to doing it.

My point is that so far as is known the spectacle-mark hairs contain some pigment which is neither external nor the result of dyeing or staining but is intrinsic, a product of hair growth, % that this probably differs only in degree (say concentration) from whatever pigment may be present in other parts of [the] same individual; & that because that is a (I won’t say the) common seat of most intense pigmentation (granular & diffuse I presume) in ordinary Pekinese.

If when you have seen my sections of skin of young puppy cases[?] you confirm what I take to be diffuse pigmentation of some of the hairs the above position would seem to be demonstrated.

For the moment the question how much the “mark” pigment is what may be called potentially congenital, how much post-natally physiological i.e. valuable, & how much adventitious either as dye from tears & mucus, if such can produce dye, or as dirt, must remain to a certain extent open.'