HEALTH. 67 



on the purity of the air that surrounds them. A clay soil 

 that retains too much moisture, or one that will not retain 

 it at all, are equally injurious and detrimental to health. 



In his '' Manual of Practical Hygiene," Parkes, the cele- 

 brated scientist, uses these words : ' ' Sand absorbs very little, 

 clay ten or twenty times more, and humus, or common sur- 

 face soil, more than forty or fifty times as much as sand." 



]^ow, when we consider that it is the excess of moisture 

 lying on or near the surface that causes vegetable decay, 

 and that the latter is the most powerful agent in breeding 

 the malaria germ, we see at once why it is that the latter 

 holds high carnival wherever soils retentive of moisture 

 are found. And, considering further that a certain amount 

 of moisture is absolutely necessary to preserve health and 

 a moderate equality of climate, we perceive also why soils 

 impervious to moisture are inimical to human life. 



Well may Parkes remark that * ' the sands are therefore 

 the healthiest soils in this respect." 



It is evident then that a permeable soil is the most health- 

 ful soil, and nowhere in the world is this quality more 

 prominent than on the sandy surface of Florida, which, 

 however, be it noted in passing, is not only and all sand 

 pure and simple, but disintegrated rock, finely comminuted 

 shell, coral, lime, and other productive ingredients. 



Dust is another factor in produciug disease, Avhose influ- 

 ence is too often overlooked and underestimated. 



On clay or humus or surface soils, the element of dust, 

 when they are dry, is ever present and ready to rise up 

 into baleful activity on the slightest provocation, as a 

 breath of wind, or even a passing footfall of man or beast. 



And here is another of Florida's safeguards. Her soil 

 is generally sandy, and sand produces dust fine enough to 

 be held in suspension in the air in such small quantities as 

 to become immaterial as to any harm it can do. There is 



