Influence of Agricvlture on Health. 217 
All that can be conceived of the excess of refinement in the 
perfection of the horticultural and aejricultural arts, was here ex- 
hibited. The villas and gardens of Lucullus and Pliny, in their 
extent, in the variety and beauty of their unrivaled collections of 
natural and artificial productions^ in the enormous outlays ex- 
pended in their embellishments, exceed every thing similar of 
which we have any account. A variety of circumstances operat- 
ing through successive ao;es, and ending in the neglect and de- 
clension of these arts, have resulted in changes in this country, 
w-hich are forcibly depicted by a modern writer. In speaking of 
malaria. Dr. Macculloch says: 
"Let us turn to Italy. The fairest portions of this fairy land 
are a prey to this invisible enemy; its fragrant breezes are poi- 
son; the dews of its summer evenings are death; the banks of its 
refreshing streams, its rich and flowery meadows, the borders of 
its glassy lakes, the luxuriant plains of its overflowing agricul- 
ture; the valley where its aromatic shrubs regale the eye and per- 
fume the air — these are the chosen seats of this plague, the throne 
of the malaria. Death here walks hand in hand with the sources 
of life, sparing none; the laborer reaps his harvest but to die; or 
he wanders amidst the luxuriance of vegetation and wealth, the 
ghost of a man, a sufferer from his cradle to his impending death; 
aged in childhood, and laying down in misery that life which 
was but one disease. He is even driven from some of the richest 
portions of this fertile, yet unhappy country ; and the traveler con- 
templates at a distance deserts, but deserts of vegetable wealth, 
which man dares not approach — or he dies." 
In our own country, the influence which the cultivation of the 
soil exerts in modifying or controling disease is seen on a 
broad and extensive scale, and is the observation of every one. 
The removal of a portion of the primitive forests is the first ob- 
ject of the husbandman. No sooner is this accomplished than a 
variety of diseases, chiefly of malarious origin, supervene. These 
continue until, by various agricultural processes, materials con- 
tained in the soil capable of generating diseases are exposed to 
the chemical action of the atmosphere, and complete decomposi- 
tion is efl^ected. Generally in proportion as this is accomplished, 
miasmal diseases disappear, until at length a comparatively health- 
ful condition is restored. 
That marshy districts, in all countries, under favorable circum- 
stances, are the generators of certain maladies, we know by expe- 
rience, but medical knowledge, with all the aid which it has de- 
rived from the most caieful chemical analysis, has hitherto failed 
in informing us what is exactly the composition of these subtle 
emanations, which are the probable cause of peculiar diseases. 
That certain powerful agents are in operation is sufficiently appa- 
