Page:McCosh, John - Advice to Officers in India (1856).djvu/248

 by strangers. There are in general good grounds, for the reputed character they bear, and though it be only a popular opinion, it is the safest plan to retain it.

The state of sleeping or waking materially affects the liability to miasma: a person may pass through an unhealthy country with safety if awake, whereas if asleep he will most likely be attacked; as if the vis medicatrix that protected the constitution when awake, went to sleep along with its master, leaving him unprotected.

It is also curious that miasma may be effectually shut out by tying up the head in a gauze veil, which acts like the wire-gauze of the safety lamp. Hence an advantage of the native mode of sleeping with the head and body wrapped up in a cloth,which no doubt saves them from many a fever. A belt of high trees intervening between a marsh and a town, is known to afford a similar exemption to the inhabitants. Numerous instances exist of towns becoming suddenly unhealthy after the cutting down of such high belts of trees, as well as other instances of towns being protected by having a grove of trees planted between them and the marsh. Miasma seems capable of accumulation in the soil, and the breaking in of old forest land is generally attended with much sickness. Hence cantonments suddenly established on the site of a cut down forest are at first very unhealthy,