DIET. 157 



time, the power of producing heat is diminished; as a con- 

 sequence there is less reaction against physical agents, and a 

 greater risk of being assailed by disease. It is, therefore, very 

 imprudent to sleep with open windows, or, at least, with 

 such as admit a current of air to pass over the sleeping body. 

 And yet this is a practice generally followed, with a view to 

 enjoying the cool of the night. Sleeping in the open air has 

 not the same ill effects. 



Besides these general rules, there are others which are 

 specially applicable to persons living within the limits of marshy 

 places. The effluvia arising from such localities exercise their 

 influence on the natives as well as strangers ; and the suggestions 

 I am about to offer are intended for both classes of persons. 



Any individual dwelling near a marsh ought to make use of 

 animal food, drink beer and porter, or spirits and water in the 

 proportion of one pint of the former and thirty of the latter : 

 the water should be filtered through charcoal. If engaged in 

 rural avocations, before going out in the morning he should take 

 some strong coffee, chocolate, or tea, with a little bread ; in fact, 

 he ought never to commence his labours with an empty stomach. 

 Again, he should not venture out at an early hour when the dew 

 is still abundant on the field, or during rain, unless dressed in 

 coarse woollen garments, say serge trowsers and a flannel jacket; 

 both should be made large. He should not follow the practice 

 of wearing socks, and, on coming home even for a short time 

 he should change his wet for dry shoes. If possible, he should 

 avoid exposure to the action of effluvia either at sunrise or sun- 

 set, as they condense at night and seem to evolve or disperse 

 with renewed energy in the morning ; and, as the human frame 

 is more liable to be acted upon during slumber, all outer 

 entrances to dwellings ought to be closed before sunset, and 

 re-opened some time after sunrise particularly those of the 

 sleeping-room ; screens made of canvas, or metallic sheets, should 

 be also placed at the draughts of doors and windows, as a 

 protection against the introduction of miasma. 



Individuals should be very careful in protecting themselves 

 against humidity, for I have come to the conclusion that this is 

 one of the most active causes of disease. It is humidity, and not 

 heat, which may be said to be productive of fever. Yellow fever 

 generally prevails during the rainy season, as also dysentery. 



