Karl Pearson 
245 
varies immensely in man. Now besides the superficial pigment, there occurs 
in man internal pigment, notably in certain brain centres, internal ear, liver, 
kidneys, siiprarenals, lungs, etc. It can scarcely be doubted that this internal 
pigmentation pla3S some part in the case of several of the organs mentioned, 
possibly a most important part in the case of the brain centres, the suprarenal 
glands, and the internal ear. Now is there any reason for supposing that this 
pigmentation varies like the superficial pigmentation in intensity and locality ? 
If so, what are the signs, outward and visible, of incomplete or partial internal 
albinism ? Where would it be most reasonable to look for the occurrence of such 
cases ? It is noteworthy that pigment superficially injected into an albino does 
not remain on the surface, but is fixed by the suprarenals, liver, spleen and lungs ; 
it is eliminated by the kidneys and intestinal epithelium. In Addison's disease, 
not only bronze areas but leucotic areas occasionally appear. It would seem reason- 
able therefore to suppose that there is not absolute independence between internal 
and external pigmentation ; other cases could be cited, but the suggestion made 
is merely that it is not wholly unreasonable to look first for defects of internal 
pigment in those individuals or stocks where we find defects of external pigment. 
Of course it is logical in the first place to demonstrate that internal pigment 
occurs in albinos at all. Adler and M'^Intosh's case throws no light from the 
human albino on this point; no more did Buzzi's. But Mr O'Donoghue* kindly 
investigated some albino rabbits, rats and mice for me and he assures me that 
internal pigment does occur in these as in normal rats and mice. We may assume 
that this is true for human albinos, but this is just one of the points which need 
elucidation as the occasion arises. However, the suggestion made is that it might 
be reasonable to look for defects, partial or incomplete of internal pigment, in the 
same stocks as we find albinism occurring in — either in the case of albinotic, 
or in the case of non-albinotic members. 
I now pass to some special points. The partially albinotic cat, the cat with 
white hair and blue eyes, is invariably deaf. Recent histological examination 
of such cats has shewn that among other important deviations from the normal 
in the internal ear, the walls of the perilymph chamber lack pigmentation. We 
are not justified as yet in saying that this is related to the deafness, but the 
possibility that it is must be borne in mind. I am not aware of any careful 
histological examination of the pigment in the internal ear of congenital deaf- 
mutes. That some forms of congenital deaf-mutism arise from partial internal 
albinism is conceivable and worth inquiring into as opportunity arises. 
* "I have found that the absence of pigment so noticeable in the external appearance of albinos does 
not seem to affect the internal organs. In examining the viscera of albino rabbits I found it impossible 
to discover any difference in colour that would enable them to be distinguished from those of normal 
animals. The spleen, liver, bile, kidney, adrenal body, Peyer's patches and salivary glands are to all 
appearances quite similarly coloured. Two rats and two mice, one of each pair being an albino and the 
other normal, gave similar results on examination and in addition the mesenteries of both normal and 
albino were alike in containing pigment cells whose presence was demonstrated by silver nitrate." 
Chas. H. O'Donoghue. 
Biometrika vii 32 
