164 
ANTHROPOLOGY: A. E. JENKS 
THE FAILURE AND REVIVAL OF THE PROCESS OF PIGMEN- 
TATION IN THE HUMAN SKIN 
By A. E. Jenks 
DEPARTMENT OF SOCIOLOGY AND ANTHROPOLOGY, UNIVERSITY OF MINNESOTA 
Received by the Academy, February 15, 1916 
In the year 1914 I published an illustrated study entitled Piebald 
Family of White Americans. 
Further research shows that my conclusion then [one of Hhe appar- 
ent positive results of this [that] research'], namely, that the spotting 
of the skin was due to 'progressive albinism,' was correct. To get 
the matter fairly before us I quote herewith my former conclusions, to- 
gether with explanations which accompanied them. Attention is es- 
pecially directed to number 4 below: 
Without going further into details at this time, I may summarize the 
apparent positive results of this research so far in hand, as follows: 
That in the family before us we see — 
1. Hereditary spotting of the skin. 
2. The character of spotting behaves as a simple Mendelian dominant. 
3. The piebald persons are heterozygous for this character of spotting. 
4. The condition of spotting is albinistic, and is progressive rather than 
fixed, giving progressive albinism — sometimes called dynamic leucosis. 
It may be well to present here definitions of albinism in its three com- 
monly recognized phases: 
Complete albinism affords no visible pigment an3rwhere in skin, hair or 
eyes. 
Incomplete albinism aft'ords visible pigment of various degrees of dif- 
fusion everywhere in skin, hair, and eyes. 
Partial or imperfect albinism affords visible pigmentation limited to areas 
separated by unpigmented areas. This gives 'piebald' and 'spotted' cases. 
Concerning the probable close interrelation between these various phases 
of unpigmented skin, Pearson says: 
When we consider the relative rareness of complete albinism, of the spotted or splashed 
condition and of xanthism, their relatively frequent coincidence in^ the same stock suggests 
that these abnormal pigment conditions are not wholly independent, and that as a working 
hypothesis it is reasonable to suppose that complete albinism, partial albinism, incomplete 
albinism, and xanthism, all static forms of leucosis, are phases of the same process and are 
probably linked with leucoderma and possibly other forms of dynamic leucosis. By 'linked' 
we suggest that they mark the complete, incomplete, local, or progressive failure of the same 
metabolic process, which may never start at all, never start in certain areas, or be imper- 
fectly started, and again being started may fail to maintain itself; further, that every vari- 
ety 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."^ 
