j64 philosophical transactions. [anno 1744. 



the milder effluvia of whites. The contagion of pestilential fevers proceeds from a 

 subtilizition and volatalization of the perspirable humours, by the effects of a 

 preceding fever, as often, if not more often, than from any external putrefaction, 

 or mineral exhalation. Hence this acrimony of the perspirable humours of black 

 and tawny people makes them subject to malignant and pestilential fevers, from 

 the same causes which breed only putrid benign fevers among whites ; and in 

 them these fevers are more apt to turn contagious, as they themselves are to be 

 infected with such contagion. Hence seem to have proceeded the first seeds of 

 the measles and small-pox, with the African or true plague. Hence also pro- 

 ceeds the rank smell, or peculiar foetor of dark-skinned people. 



7. This acrimony of the perspirable humours, with the thickness and density 

 of the skins of black and tawny people, or imperspirability of their bodies, makes 

 them subject to many severe cutaneous diseases, accompanied with a contagion, 

 which white people never feel, but by infection from them ; and then these dis- 

 eases appear in other shapes, with milder symptoms, than in the dark-skinned 

 people which breed them. These diseases, which he has observed among them, 

 may be referred to the elephantiasis Graecorum, or lepra Arabum, two species of 

 which are called the yaws, and the joint-evil ; with some others, not named, ap- 

 pearing in obstinate subcutaneous ulcers. But the elephantiasis Arabum, to 

 which the negroes are also subject, is not a cutaneous distemper, as has been 

 thought, but a peculiar kind of cachexy, accompanied with an atrabilious ca- 

 cochymy, as in those afflicted with the haemorrhoids; that being much the same 

 distemper in the legs, as this is in the haemorrhoidal veins. The peculiar dis- 

 eases of white people analogous to these of the blacks, and which the blacks 

 never have, are the lepra Graecorum, at least with furfurous desquammations, 

 the itch, scurvy, essera, and some smaller ones of that kind. This cutaneous 

 malady of the negroes, called the yaws, laid the first foundation of the lues ve- 

 nerea ; which became to differ from it only by the part affected, and the particu- 

 lar manner of receiving the infection, after being transplanted into another colder 

 clime, on people of a different complexion ; the virulent acrimony of the cuta- 

 neous contagion being inviscated, and consequently mitified, by the semen which 

 received it ; the subtiler parts of the contagion being likewise exhaled in the white 

 people, on account of the perspirability of their bodies, though the distemper was 

 driven more on the internal organs, on account of the coldness of the climate ; 

 and so appeared to partake less of a true cutaneous malady, after this lues vene- 

 rea was first propagated to Europe. Hence it is originally a cutaneous malady, 

 only to be cured as such ; the venom which attends it, and gives rise to it, being 

 to be evacuated, most surely and effectually, by the pores of the skin, as it was 

 originally bred by the acrid effluvia which pass through them. Hence the na- 



