rom the Journal of the Tölegruph. Among the many invostigations now being made of the chemioal action ot' light, thore are none more interesting or more important llian those which are (lirected to the observation oí its eíFects on the health. It has been observed ljy Dr. Web■i' t!i:it tlio sensibility of the skiir is viu-y much incveasnd in thosc jvirts ot' the body wbioh are alwnys nxposed to tho light, and this difFerence his even been measïired by that eruinent physicia. Tiiis lemaxkable faot is ospocially observable on persins siiftotiErg ïrom small-pox, the S'jvority of tho skin disease beiiig visibly augintnted if the patiënt be nok coufinod D a darle room. Dr. Waters b is recontly published a paper on this subject, in whioh he statcs that if the room bu darkciii-l 80 thnt a single ray can eater it, the effect is to arrest the disease at the pupular or vosicu'ar stage; it nevor becouics puralent, and tho skin botweon tho vesicles is nevor inflamed or swollen ; Uqnar eanguinis is not changod into pus, nearly all the iiin and ttchtng áiü abcant, timl thü sinoll is, if not uutirely rjmuved, gre'atly diuiinished. Anotlior advantiig.;, important in a tboropeutioal poiiit of viow, is tliu osaistanoe given to Dtediñnes, the' absence of tight iaoreas.nj the xcrotory tovretaoï the skin.