1838] 



FARMERS' REGISTER 



S21 



following malerials. let, The putrid and stiiikint!; 

 water of stajruaiit ponds, partially dried by the 

 heat of summer. 2d, The mud bottoms of fucIi 

 ponds, or oi' streams reduced by drought, rich in 

 decomposed vegetable matter, and lelt bare oC wa- 

 ter only in summer. 3d, Fresh- water marshes, of 

 vegetable soil, frequently, but not regularly, cover- 

 ed by the tides. 4ih, Fresh-water marshes, laid 

 dry "by embankments, and thereby permitted to 

 rot away rapidly. 5ih, The meeting of salt and 

 fresh vva"ters on land full of vegetable matter. 01" 

 these several and most important sources of mala- 

 ria, 1 deem the third (fresh-water marshes in their 

 natural state) to be the least hurtful ; and that the 

 sources numbered 1st, 2d, 4th, and 5th, increase 

 ill virulence in the order in which they are named. 

 The greater evils produced by the last are univer- 

 sally admitted, but still by an erroneous deduction 

 i'rom the premises. The belt ol' the tide-water 

 region of Vii'ginia, in which tlie fresh water flow- 

 ing down the rivers mingles with the refluent salt 

 water from the ocean, is well known to be more 

 subject to autumnal diseases, than any other ex- 

 tensive space in the country. The breadth of this 

 belt varies much in different seasons. The parts 

 of the rivers in which the fresh and salt waters 

 meet, and where each alternately has possession, 

 us tlie tide ebbs or flows, may be but a i'cw miles 

 wide, and even that space is not stationary. But 

 if the limits of this belt be fixed by the highest 

 pomts to which the rivers have been known to be 

 brackish, in driest summers, and by the lowest 

 points where they are fresh in winter, then this 

 belt may be considered for the time as 40 or 50 

 miles wide, and, in length, stretching across all the 

 tide-watel's of the state. But in the much narrow- 

 er space where this mingling of tlie salt and fiesh 

 waters usually takes place during the heat of sum- 

 mer, malaria acts with most intensity. Hence the 

 genera! opinion, that it is simply the meeting and 

 mingling of the fresh and salt waters which cause 

 disease. This is not so, or but in a very slight de- 

 gree. It is either the passage of fresh-water over 

 salt-water marshes, or of salt-water over li-esh- 

 water marshes, that causes the great production 

 of malaria, and disease. This is an important 

 distinction, and the truth or error of the position 

 deserves tlie most careful investigation. II' the 

 mere mingling of the waters were the cause of 

 sickliness, any relief for this part of the evil 

 would be hopeless, as the waters 7tiust meet and 

 mix together, somewhere. But if it be as I sup- 

 pose, the evil may be greatly restrained by works 

 of art, or by simply preventing the unnatural 

 accumulation of vast reservoirs of fresh wa- 

 ter in mill-ponds, which when discharged, by 

 breaches in the dams, or by opening the flood-gates, 

 overflow salt-marshes, which theliatural or unob- 

 structed stream never could have covered. 



Salt-water marshes, not touched by li-esh-water 

 streams, are not unhealthy to any considerable 

 extent. This is susceptible of proof by innumer- 

 able examples in Virginia on the borders of the 

 ocean, or of the waters of the Chesapeake bay. 

 It is rare, however, to find a large salt-marsh at- 

 tached to extensive iiigh-land, which is not reach- 

 ed by some small stream; and every sali-marsh 

 of course must sometimes be well washed and 

 lieshened by (he heaviest fialls of rain. Thereibre 

 all must, dighiiy and at some times, be prejudicial 

 to healtli. These, however, are exceptiont of but 

 small practical or sensible operation. 



The view here taken of (he manner in which 

 malaria is produced most certainly, and acts most 

 injuriously, though not sustained by any known 

 authority in this country, nor by any other pre- 

 cisely as stated here, is not therelore presented as 

 orifinal. I derived it, and thence deduced my ap- 

 plication to this country in a modified form, lioin 

 the interesting report on the malaria of Italy by 

 (Jaetano (Jcorgini, of which the substance was 

 published in tvvo difli^rent papers in the Farmers' 

 Register, (p. 502 of Vol. IV, and 460 of ^■ol. V.) 

 In This report the author shows by the most con- 

 clusive argument and facts, that the^ irregular ir- 

 ruptions of sea-water over tracis of marshes, or 

 other low-grounds, of fi-csh-vvaler alluvial ibrma- 

 tion, caused the long continued and worst eflecis 

 of malaria; and that by simply guarding against 

 the entrance of sea-water, the country was re- 

 stored permanently to healthiness. He says no- 

 thing of the reverse operation, the irregular flood- 

 ings, with fresh-water, of salt-marshes. But what 

 is "produced by the one, can scarcely fail to be as 

 well produced in the other case. The mode in 

 which the effect is produced is not attempted to be 

 explained by the learned author quoted above; nor 

 does any explanation seem sufficient to my mind. 

 The rapid and abundant production of malaria 

 may perhaps be aided, if not entirely caused, by 

 the luxuriant cover of fresh-water jilants, in the 

 one case, being partly killed, and made ready for 

 putrefaction, by being covered by salt water; and 

 in the other case, in this country, by a like inju- 

 rious operation on the plants peculiar to salt 

 marshes, produced by the overflowing of fresh, 

 water. We know that certain plants flourish best 

 in salt and wet soil, as others do in wet soil entire- 

 ly free from salt; and that respectively with these 

 difierent growths, the salt and the fresh marshes 

 are heavily covered. It must follow from a sud- 

 den change in the condition, from salt to fresh, or 

 the reverse, that the health of the entire growth 

 must be greatly injured, and much of it subjected 

 to death and decay. 



The next most fertile source of malaria, (or 

 perhaps what is even of greater malignity, for the 

 small space occupied,) is presented in what is en- 

 tirely the work of man— the miscalled improve- 

 ments made by embanking and partially or entire- 

 ly drying tide-marshes. The soils of these marsh- 

 es, as I have ascertained by careful analyses, are 

 composed, for about half their weight of vege- 

 table matter, and probably nine-tenths of their 

 bulk is of that 'material, destructible by decompo- 

 sition, when circumstances are favorable to that 

 result; and drainage and cultivation produce pre- 

 cisely the condition which is most favorable. 

 When covered twice every day by flood-tiile, a 

 marsh soil of this kind, though composed of the 

 most putrescent materials, is but little subject to 

 decomposition; because being always thoroughly 

 water-soaked, even when not entirely covered, 

 and by water continually changed, the air is too 

 much excluded, and the wetness is too much in 

 excess, to favor the progress of decomposition. 

 When (he marsh rises so liioh as not to be cover- 

 ed by the daily or frequent tides, then decomposi- 

 tion's more favored by the drier state of the sur- 

 face, and to a greater extent, malaria is evolved, 

 and health injured. Hence the inference, that 

 the. higher and the drier the marsli, the more it is 

 injurioui to health But uo auon a:, -uch a vege- 



