96 Dr Stark on the Influence of Colour on Odours. 



The result of my investigations has led me to form a very 

 different opinion. It is to white-washing that I should attri- 

 bute much of the good effects that have been found to follow 

 the purifying means generally employed. In such cases I 

 should trust more to whitewashing the walls, personal cleanli- 

 ness, and free ventilation, for destroying or diminishing the 

 effects of supposed pestilential or hurtful effluvia, than any other 

 measures. Acid and other fumigations, except chlorine, only 

 disguise, but do not destroy, the property of animal effluvia to 

 produce disease. 



In the late epidemic cholera here, it is well known that this 

 disease broke out in the village of the Water-of-Leith, situate 

 a little to the north-west of Edinburgh, and lying on both sides 

 of the stream of that name. Many of the inhabitants were 

 seized with the disease, and fell victims to its severity. If a 

 damp and low situation, with accumulated filth of all kinds, 

 render disease more fatal, this was certainly a place likely to 

 suffer severely, and at first it did so. But the Board of Health, 

 with that promptitude for which they were distinguished, quickly 

 got all the filth, so far as practicable, removed, the houses fumi- 

 gated, and the walls white-washed outside and inside. By these 

 means the disease seemed at once to be arrested, its virulence 

 was much abated, and it gradually declined. The fumigations 

 in this case could only act upon the deleterious emanations in 

 the air at the time ; but unless constantly renewed, could not 

 affect the fresh emanations generated from those labouring un- 

 der the disease. The necessary ventilation must also have 

 speedily carried off the chlorine. In white-washing, on the 

 other hand, although it had no specific influence upon the 

 contagious effluvium, yet, by constantly presenting a reflecting 

 surface, prevented the absorption of the emanations by the 

 walls, and thus tended with moderate ventilation to keep the 

 air of the apartment pure. Dirty-coloured walls, on the con- 

 trary, would readily, as has been demonstrated, absorb the 

 noxious odours, and as soon as the eflect of the fumigation 

 was over, gradually give them out again. 



The good effects of white-washing appeared strikingly in 

 another instance at this particular time ; for I venture to assert, 

 that if human means had any influence on tlr's disease, Edin- 



