364 Anomalies of Pigmentation among Natives of Nyasaland 
part of the Battalion had returned from Somaliland. I was surprised to find when 
the Battalion as a whole stripped that the men who had been on foreign service 
were many shades darker than those who had remained in the Protectorate of 
Nyasaland. The Somali men were as black as any native I have ever seen, and by 
comparison the Nyasaland men looked like members of a yellow skinned race. 
The reason for this difference was that in Somaliland all fatigues had been done 
bared to the waist, while the men remaining in Nyasaland had not been without 
regimental clothing (khaki tunic or blue jersey) for years. 
I obtained a similar result by keeping several turns of bandage round the chest 
of a native for eight weeks. 
Again, I would refer to my observations on the skin colour of the penis. One 
may say that normally the ensheathed glans penis is not deeply pigmented; the 
pigmentation of the partially covered glans is proportional to the want of cover. 
The glans of a man who has been circumcised is invariably black. Therefore 
though always pigmented to some degree because skin pigmentation is a racial 
characteristic, the process is only completed as the result of exposure in the 
majority of cases. Special notice must be taken of the case of albinism of the 
penis; wherein, after circumcision at the age of 26 years, the skin of the glans, 
which was absolutely albinotic and would doubtless have remained so all the man's 
life had he not been subjected to operation, developed a spot of pigmentation a 
year later. How could this case be accounted for on the theory of structural 
defect* ? It is a fact worthy of remark that the penis should be the commonest 
site to find a spotling albinism and that it should occur in close on 4°/ 0 of 379 men 
taken at random; excluding the circumcised, it occurred in nearly 6°/ 0 . 
In a large number of albinos we have seen there is a marked ability to form 
pigment {vide spotted albinos, and those of Class IV, who develop a certain amount 
of pigment in the skin but not in the hair and again those in whom pigmentation 
is only delayed, cases C 11, C 12 Sawali) which does not appear to point to 
defective structure of the skin, the explanation favoured by Pearson, but would 
rather suggest the action of some internal secretion. The hyperpigmentation of 
Addison's disease is due to the perverted action of the suprarenal glands which are 
commonly the seat of the destructive lesions in that disease, and it seems quite 
possible that normal pigmentation in negroes is due to a somewhat similar cause ; 
light may act not directly on the skin cells but on some tissue or substance which 
determines the formation of pigment in the skin. 
Many of the characteristics of persons living in tropical countries are akin to 
symptoms occurring in suprarenal insufficiency. 
With regard, however, to the factor of abnormality of skin structure brought 
forward by Pearson, I would again refer to the conditions as seen in the sections of 
* [I would venture to suggest that the very facts that the pigment developed in a spot only in this 
case, and that pigment occurs in localised patches only in piebalds, or in freckles and isolated locks of 
hair in otherwise complete 'albinos do indicate a differential structure; the local absence of a ferment — 
without a cause for its absence — seems to me an inadequate explanation of leucosis. Ed.] 
