6 
Proceedings of the Royal Society 
dom shed their beneficial influence. The resistless epidemic found 
an easy prey among a people whose physical organisation had not 
been matured under those benign influences of solar radiation 
which shed health and happiness over our fertile plains, our open 
valleys, and those mountain sides and elevated plateaus where man 
breathes in the brighter regions of the atmosphere. 
Could we investigate the history of dungeon life of those noble 
martyrs whom ecclesiastical or political tyranny have immured in 
darkness, or of those felons whom law and justice have driven from 
society, we should find many examples of the terrible effects which 
have been engendered by the exclusion of those influences which 
are necessary for the nutrition and development of the lower 
animals. 
Dr Edwards applies to man the principles which he deduced from 
his experiments on animals; and he maintains that, “in climates 
in which nudity is not incompatible with health, the exposure 
of the whole surface of the body to light will be very favourable 
to the regular conformation of the body.” In support of this 
opinion he quotes a statement by Humboldt, that among the 
people called Chaymas, who live under the Equator, both men and 
women are very muscular and have fleshy and rounded forms, and 
that he had not seen a single individual with a natural deformity.” 
“ I can say the same,” he adds, “ of many thousands of Caribs, 
Muyscas, and Mexican and Peruvian Indians, whom I have ob- 
served during five years. Deformities and deviations are exceed- 
ingly rare in certain races of men, especially those which have the 
skin strongly coloured.” 
If light thus developes in certain races the perfect type of the 
adult who has grown under its influence, we can hardly avoid the 
conclusion drawn by Dr Edwards, “ that the want of sufficient light 
must constitute one of the external causes which produce those 
deviations in form which are observed in children affected with 
scrofula, — an opinion supported by the fact that this disease is most 
prevalent in poor children living in confined and dark streets.” 
Following out the same principle, Dr Edwards infers, “that 
when these deformities do not appear incurable, exposure to the 
sun is one of the means tending to restore a good conformation.” 
“ It is true,” he adds, “that the light which falls upon our clothes 
