170 DISEASES. 



When tliis disease first came under my notice in the early part 

 of 1882, I was unacquainted with what had been previously written 

 on the subject. I accordingly made a microscopical examination of 

 the affected skin and arrived at the conclusion, previously formed 

 Dy those far more competent to express an opinion than myself, 

 that the eruption was an inveterate form of body-ringworm. As it 

 is to be seen affecting the skin of young children in the form of 

 limited circular patches, which usually commence on the belly, it dis- 

 plays all the essential charactei's of Tinea circinata or body-ringworm. 

 Spreading all over the trunk and limbs, the eruption assumes a 

 chronic character and its typical characters become obscured. The 

 whole skin, with the exception of that of the face and scalp which 

 are not attacked by the disease, is covered by a great number of 

 wavy desquamating lines partly concentric in their arrangement ; 

 and on account of the intervals between the lines being of a paler 

 hue, the whole skin obtains a singular marbled appearance. • 



To such a degree is the skin implicated in some cases of the 

 disease that the rapid desiccation and desquamation of the epidermal 

 cells lead to a partial decoloration of the deeper parts of the cuticle^ 

 as though the rate of the production of pigment was less rapid than 

 the rate of its removal in the desquamative process. This disease,^ 

 in other words, tends to decolorize the skin. From this cause, one 

 occasionally meets with a native whose skin as compared with that 

 of his fellows is of a pale sickly hue. The tendency to produce a 

 lighter colour by the too rapid destruction of the pigment is 

 especially noticeable in those cases where tlie bod}' is only partially 

 covered with the eruption, there being a marked contrast between 

 the paleness of the affected surfaces and the dark hue of the healthy 

 skin. The influence of this cutaneous disease on the colour was re- 

 marked by Commodore Wilkes amongst the natives of the Depeyster 

 Islands in the Ellice Group. He refers to the skin of those affected 

 as much lighter than in any Polynesian race he had hitherto met 

 with.' The same effect of this disease was noticed bv Mr. Wilfred 

 Powell amongst the natives of New Britain.^ 



I have entered somewhat at length into the subject of the partial 

 decoloration produced by ihis eruption, because it has a bearing on 

 that " quaestio vexata," the causes of race-colour. Pathology, in 

 fact, affords more than one instance of changes, almost of a perma- 



1 " Narrative of the U.S. Exploring Expedition," London, 1845 ; vol. V. p. 40. 



2 "Tlirwe years amongst the Cannibals of New Britain," London, 1883, p. 8G. 



