362 Anomalies of Pigmentation among Natives of Nyasaland 
that every variety of this failure may individually or collectively be associated 
with certain stocks, which may either show hereditary failure of one phase, of 
several, or exceptionally of all phases of pigment metabolism." 
This hypothesis gives a masterly summing up of the position, warranted, I think, 
if only in the light of my own series of cases. 
If we seek the cause in some inherited defect we might suppose that some 
pigment-controlling determinant by its absence causes failure of natural pigmenta- 
tion. Its perfect or imperfect impotence may be a racial feature of certain forms 
of parental albinism. This impotence may be a racial feature of certain parental 
stocks or produced by some degenerating influence of the somatic on the germ 
cells of the individual parent such as must occur in the case of an inherited 
character arising in the parent as a " sport." 
This absence of certain determinants does not carry us very far, for the question 
suggests itself: how do such determinants act on the normal body metabolism ? 
It has been suggested that some ferment necessary for pigment formation such as 
tyrosinase is absent. 
As Pearson says, " it must however be remembered, (i) that the absence of the 
ferment in the albino must correspond to some abnormality in the zygote and 
ultimately to some defect in one or both gametes. This defect can hardly be an 
absence of ferment, (ii) The materials for development are supplied in utero by 
the mother, who may be (a) herself pigmented, and (b) produce at the same time 
pigmented and unpigmented twins. It would appear that she is thus able to 
provide the ferment for one and not for the other offspring." 
One might postulate ferment determinants. Pearson suggests " that the 
ultimate difference between the normally pigmented individual and the albino, 
will be found after all to be one of structure ; the failure of the normal metabolic 
process is due to differential structure in the albino. If there be local absence of 
ferment it may possibly be that the structure does not permit of its reaching its 
destination," and mentions in support of this view that albinos may have a 
considerable amount of diffused pigment in their hair. 
He also says that it would be difficult otherwise to understand how in cases of 
partial albinism the ferment should be confined to some portions of the skin and 
be wanting in others. Facts gleaned from my own observations which seem to 
have a direct bearing on some of these points I may here refer to. I should like 
first to mention some observations on the natural rate of pigmentation in African 
natives. 
Pearson states that a black baby at birth almost resembles a white one in 
colour, and quotes Dr Strachan*. With all deference to Dr Strachan, I most 
* [This does not seem adequately to represent the views of the authors of the Monograph, or of 
Dr Strachan. The reader is referred to pp. 120 — 124 of that work, where much of the literature on the 
subject is cited. The point involved is not the impossibility of distinguishing between a just born white 
and just born black baby, but to the fact that the black pigmentation except on the genitals and some 
other parts is relatively slightly developed at birth. Ed.] 
