Popular Science Monthly/Volume 22/March 1883/Remedial Value of the Climate of Florida




"Know ye the land of the cedar and vine,
Where the flowers ever blossom, the beams ever shine,
Where the citron and olive are fairest of fruit,
And the voice of the nightingale never is mute?"

WHEN one approaches this land, from the northward, in the winter season, having left the hills and valleys about his home covered with the cold, white mantle of winter, he is pleased and cheered by the green foliage. The breezes which touch him possess a delicious softness and a fragrant, spicy aroma. When, at the shores of the St. John's River, he looks over miles of clear and unruffled water, many miles in width, like an inland lake, and reaching far away, hundreds of miles to the south, fringed by green inlet and headland, bearing the tropical foliage of cypress and orange, palmetto and palm; when the mild sunshine, falling so softly upon forest, bank, and river, has penetrated him till he feels a gentle warmth flowing through his veins; when a delicious languor has possessed him, and it would seem perfect happiness to rest in the genial sunshine forever then he knows he has found the sweet do-nothing land of America.

Warmth is life, cold is death, and the medical study of climate is only an analysis of those conditions of heat which will best secure an abounding vitality in the healthy human organism, or restore a shattered organism to its normal physical relations.

Men, like children, continually cry for the unattainable. We would like a land in which a perfect June always prevails.

What are the factors in the climate of Florida? Heat, water, and light—warmth, moisture, and sunshine.

The health resort of Florida is the peninsular portion, averaging one hundred miles in width and projecting southward over three hundred miles, amid the waters of the Atlantic Ocean and Gulf of Mexico.

It is a flat land, composed almost entirely of sand. So much does it resemble a jetty of sand, such as we see formed at the confluence of streams, that it may appropriately be termed an ocean sand-bar, with everglades, marshes, and lagoons in the southern portion, testifying how recently, geologically speaking, it has emerged from the depths of the sea. Around this sickle-shaped peninsula the Gulf Stream, with an average temperature of 86° Fahr., sweeps from the southernmost point along the eastern shore at a distance of ten to one hundred miles from the coast. Across it the salt-laden breezes of the ocean continually play, by day and by night. Upon it the warm rays of a semi-tropical sun almost continually shine.

What are the results of these physical conditions, stated in the exact terms of meteorological science? For this purpose it is not necessary to array long tables of average temperature, mean monthly range, rain-fall, barometric pressure, relative humidity, etc.

It is sufficient to know that the average temperature of Jacksonville, for the month of November, is 61° Fahr.; December, 54° Fahr.; January, 55° Fahr.; February, 57° Fahr.; March, 62° Fahr. The rainfall in November is 312 inches; December, 3 inches; January, 3 inches; February, 212 inches; March, 412 inches. St. Augustine, Palatka, and Gainesville average 2° or 3° warmer than Jacksonville. At St. Augustine the rain-fall is less than at Jacksonville, being, November, 1·2 inch; December, 2 inches; January, 2 inches; February, 1·6 inch; March, 2·3 inches. The mean monthly range of temperature for these places during the winter months is between 20° and 30° Fahr.

These figures indicate a mild, equable, and sunshiny climate during winter for all that portion of Florida frequented by invalids, embracing a region on the east side of the State, from Jacksonville as far south as Palatka. For a country lying on a parallel with the Canaries, off the coast of Africa, they indicate a climate which in temperature approaches that of Malaga, Malta, and Algiers, but does not nearly equal them in evenness and unchangeableness, though, in point of clear, sunshiny weather, far superior.

However, from the facts given, we are unable to fix accurately the position of the Florida climate. We neither know the atmospheric humidity nor the electrical potential; and, as yet, the phenomena of nature have not been interrogated for an answer.

A cardinal question is whether the climate be moist or dry, bracing or relaxing.

It may not be amiss to note here an error committed by a professional gentleman of Jacksonville.[1] In a pamphlet on the climatology of Florida, he gives tables of the mean relative humidity of Jacksonville and other stations in Florida, and attempts to prove therefrom, by comparison with similar observations in Northern States, that the atmosphere of Florida is dry, much drier than that of Minnesota, Mount Washington (New Hampshire), Alpina (Michigan), Omaha (Nebraska), and other Northern localities. It should be remembered, however, that there is a wide difference between relative humidity and absolute humidity, and their relation is frequently diametrically opposite. Relative humidity does not indicate the amount of vapor present in the air per cubic foot, but only the tendency to deposit it in a wet state on a surface but little lower in temperature than the surrounding atmosphere. Absolute humidity, on the contrary, is the actual amount of vapor present in each cubic foot of air. To illustrate, suppose the cubic foot of air to be a hollow cubic vessel of tin. Absolute humidity is the actual amount of watery vapor contained in that tin vessel. Relative humidity is the tendency of that vapor, be it great or small in quantity, to leak out of the vessel and show itself on the outside in the form of mist or dew. Sir John Herschel says, "As a general meteorological fact, there is not merely a want of accordance, but an actual opposition between both the diurnal and annual progress of the 'degree of humidity' or 'relative humidity' of the air and the 'tension of vapor' as indicated by hygrometric observation, a seeming paradox, but one very easily explained."[2] He then shows how the relative humidity is greatest just before sunrise of each day, and the vapor tension or absolute humidity is least; that as the day advances the relative humidity diminishes and the absolute humidity increases, till the maximum temperature of the day is reached, when absolute humidity is greatest and relative humidity is least. It is also well to know, in considering this question, that air at a temperature of 60° Fahr. is capable of containing double the quantity of vapor by weight That it is at a temperature of 40° Fahr., and this ratio continues throughout the thermometric scale. Whether air at an average high temperature, like that in Florida, will contain this excess of moisture, depends only on the proximity of water whence the vapor may he obtained.

The figures of relative humidity recorded by the Signal Service at Jacksonville only indicate the ratio in per cent which the humidity of the air at the time bears to saturated air at the same temperature. But the weight of vapor in saturated air at that temperature is not given, therefore the absolute value of this percentage, so far as the records are concerned, is unknown. The basis for the calculation is, however, easily obtainable—the weight of vapor in troy grains, contained in saturated air at different temperatures (Glaisher's Table)—and will be found to increase in an ascending scale from zero. The following record of the Signal Service in Cincinnati, Ohio (Sergeant R. B. Watkins, U. S. A., observer), well illustrates the subject:

PSM V22 D662 1 Relationship between temperature and humidity.png

From the above table we see that on a day of high temperature and low relative humidity there was nearly six times more vapor in the air than on a day of low temperature and high relative humidity.

By way of comparison we here insert a table showing the mean annual and winter temperature, also the relative humidity and absolute humidity, of three winter stations. It shows the average quantity of vapor in the air at Jacksonville, throughout the year, to be twice as great as at St. Paul, Minnesota, and four times more during the winter season:

PSM V22 D662 2 Relationship between temperature and humidity.png


In consideration of these facts, we are compelled to cast aside tables of "relative humidity" as valueless when taken alone, for the purpose of determining the humidity of climates. The physical properties of vapor in the air—the absolute humidity—are essential elements which can not be ignored, and are of exceeding significance in the treatment of disease.

We have given prominence to this topic, inasmuch as the pamphlet of Dr. Kenworthy is widely circulated by the Bureau of Immigration of the State of Florida, and is quoted in a pamphlet on Florida issued by the United States Department of Agriculture, and also in the well known work on Florida by G. H. Barbour, as establishing conclusively the dryness of the climate. It well shows how figures, correct in themselves, may, by misapprehension of their import, become the source of mischievous error.

Given—a peninsular land subjected to the burning rays of a semitropical sun and surrounded by an ocean of warm water, the average temperature of which is 77° Fahr.[4]—then it is not necessary to ask the Signal Service whether the climate be moist or dry. If they supplied us with tables of absolute humidity, they could only add to our information accurate knowledge of the excess of moisture. Every breeze that blows touches the face with the softness of a moist May morning at the North. The atmosphere is delicious, balmy.

In addition to physical sensation and deductions drawn from geographical position, there are other reasons for deciding that the climate is moist. The necessity of frequently emptying closets during the summer season, and drying clothing-apparel; the impossibility of using cellars, because of the quickness with which mold destroys goods there stored; the thick formation of vert-de-gris on articles of brass; the rapid decay of structures made of wood, as compared with Northern localities; the presence almost everywhere of the Southern moss (Tillandsia), swaying in festoons from the trees—these facts tell of excessive atmospheric moisture.

Sunshine, which is so cheering to the invalid, and the absence of which is so depressing even to the well, is abundant in Florida. There it glitters continually on leaf and flower. Five years' observation at Jacksonville shows an average of only seven cloudy days for each winter month, the other twenty-three being arched by a soft Italian-like sky.

What relation electrical potential may have to climate as regards its so-called elasticity or bracing properties is yet undetermined. That it is continually fluctuating, and that it varies considerably at different places, is known. When instruments shall have been devised by which this element can be accurately recorded, we may then discover that those climates which are termed bracing possess special peculiarities as to electrical distribution.

We then estimate the climate of Eastern Florida to be mild in winter temperature, moist, sunshiny, relaxing, and for an American climate equable, though not to be compared in this respect with the Genoese Riviera.

What is the value of this climate in the treatment of disease?

We will first consider that scourge of overcrowded populations—consumption—a disease which is limited to no zone, and for which the benefit of change of climate is most frequently sought. The discoveries of Koch, of Berlin, in his researches on the cause of this disease, may, if they are satisfactorily confirmed, enable us in the future to interpose barriers to its invasion. They may also enable us to eliminate "taking cold" as one of the causes of consumption. But they will not change the nature of the bacillus tuberculosis, the habits of which, although itself unknown, have been familiar to the world for many centuries. Persons of feeble constitution, whether hereditary or acquired, will still be the subjects of its incursion, and the disease engendered by its presence will require the same treatment as heretofore, unless happily we find a remedy which will destroy these morbific germs in situ, and thus, by relieving the patient of the exciting cause, lead to immediate recovery.

It is not necessary to cite authorities to show that the prime need of a consumptive is that he shall be a great deal out-of-doors, that he shall breathe pure air, that he shall exercise, that his entire physical organization shall be invigorated. Is the climate of Florida fitted to do this? I answer, No! The climate is simply and delightfully soothing. Being so—being moist and relaxing—it will cause tuberculous deposits to disintegrate rapidly. Expectoration will be increased, and there will be no rally of the system to oppose this new call upon the strength. Instead of exercising freely and expanding his lungs as he should, the consumptive invalid will sit listlessly on the piazzas of the hotels, awaiting his fate. Hundreds are seen, wherever you go, so doing. Seldom do you see one attempting to exercise, and, if one is seen, he is moving in that sluggish and apathetic manner so characteristic of every one living there.

It is unfortunate that, of the thousands of consumptives who go to Florida, we can get no reliable statistics of the result. The people of Florida, the owners of the soil, the railroad and steamboat owners and agents, the hotel-keepers, the physicians residing there, are all so much interested personally in the prosperity of the State, which, since the close of the war, has been opened up like a newly-discovered country, that it is well-nigh impossible for them to give unprejudiced statements concerning the healthfulness of the State, its adaptation to the cure of disease, or any other subject, which even remotely touches their personal interest. A prism is placed before your eyes, and you are caused to see everything covered with the colors of the rainbow.

However, I snatched one fragment from the page of fact. During the last six months of 1881 there were thirteen deaths in Jacksonville (population 8,000[5]) from consumption, these deaths being of residents only, and excluding all non-residents or visiting invalids. This is a mortality of 1·62 per 1,000, being a greater mortality than occurred in Cincinnati during the same time, which was 4·24 in a population of 280,000, or 1·51 per 1,000. These figures do not establish the rate of mortality, from this disease, in the city of Jacksonville, for in so small a place a series extending over a number of years would be necessary. But, when facts are so difficult to find, we must content ourselves even with a straw. It is much more satisfactory to thus have an indication from a populous center, than the rate from sparsely populated country districts, which, as is well known, are comparatively immune everywhere. It may be stated, in this connection, that natives of Florida taken with consumption frequently seek other places and climates as a means of cure.

In endeavoring to show the unfitness of Florida for consumptives, I have spoken of the disease en bloc, and made no reference to the different types, as I believe it better to convey the impression that Florida is not suitable for any type of the disease. Possibly in the rare inflammatory kind, with dry and heated bronchial tubes and beginning laryngeal symptoms, the soothing and relaxing air of Florida may be of temporary advantage. But the forecast of such cases is seen ab initio, and we do not look for a cure, such as may frequently occur in cases of the more chronic sort, when proper medicinal treatment is given and a proper climate is selected.

We do not mean to say that cases of consumption never improve in Florida. Undoubtedly there are cases which get well in Florida, just as there are in every locality, and even at home.

Turning from consumption, we will look on the opposite side of the picture. Are there no diseases of the lungs in which this delightful climate is beneficial? Undoubtedly; and it is the efficacy of the climate in this other group of diseases—the bronchial, often wrongly diagnosed as consumption—that has given reputation to the climate. The "taking of cold" in Florida is a comparatively infrequent event. Even when one does take cold it is only manifested by slight sneezing, and that is the end of it. There is no tendency to acute inflammation of the Schneiderian membranes, the extension by continuity to the fauces, larynx, trachea, and bronchial tubes; in fine, to that compound of malaise, difficult breathing, soreness of the chest, and cough, termed a "severe cold," which is so excessively frequent in this latitude, and which, often repeated in certain constitutions, leads to chronic inflammation and diminution of the caliber of the bronchial tubes, to dilatation of air-cells, to bronchorrhœa, and all those attendant evils which are little less baneful than consumption itself. For those in whom frequent colds have induced the condition of chronic bronchitis, I believe there is no better climate than Eastern Florida, and those in comparatively good health who suffer from repeated colds without other ill effects will find in that climate freedom from t the inconvenience. That other condition termed winter cough, frequent among people advanced in years and which is little other than chronic bronchitis with a quiescent period during the summer months, will also be entirely relieved in that land. Indeed, if the person removes there for life he will soon become unconscious that he ever had such an affliction.

Chronic laryngitis, and pharyngitis granulosa, or clergyman's sore throat, will also be decidedly benefited by winter sojourn or permanent residence in Florida.

In the spasmodic constriction of the bronchial tubes—asthma—it can only be said that many cases will be entirely relieved in Florida, while with some it will fail, and, if one is to be exiled in the interest of health, there is probably no pleasanter place for enduring semi expatriation.

A climate of this kind is also favorable to the prolongation of the life of those afflicted with chronic Bright's disease of the kidneys—chronic parenchymatous nephritis. The person will be little exposed to chilling of the surface of the body, which arrests cutaneous perspiration, congests the blood-vessels of the internal organs, and forces excessive work on the already damaged cortical net-work of the kidneys.

Sufferers from muscular and chronic rheumatism find the genial warmth of this region softens the unpliable and painful muscles, and loosens the rigid tendons, while the increased secerning activity of the skin removes the morbid humor, whatever that may be.

For none do I know a land more delightful, than for him who, by long and severe mental activity, has exhausted the vital battery of nerve-force and disturbed the harmonious balance between the varied complex nerve-circuits. The person who suffers from this condition, sometimes called nervous prostration, and which often passes under other cognomens, will there find a panacea. The soothing softness of the climate invites to continuous repose, and for him perfect rest is a prelude to restoration; repair of tissue gains upon waste, the nerve currents gradually resume their normal course and vigor, and a return of health results.

Old age crawls shivering along our cheerless streets, the frigid northern blasts fluttering the garments about his attenuated limbs, chilling the blood till stasis occurs in some vital organ, and inflammation and death result. There, the old man pursues out-door life fearless of frost or intense heat, and, in a prolonged and painless existence, forgets that his summer is gone, and the snows of winter are upon his head.

In closing this paper, some reference to places in Florida most suitable for invalids may be of interest.

Leaving Jacksonville in the afternoon of any day, by one of the beautiful side-wheel steamers, the passenger, sitting on the forward guard, sees unrolled before him a semi-tropical scene. The vessel makes its way in the midst of a broad stream of placid stillness, whose shoaling shores are curved and fretted by inlet and headland, bearing above them the rich luxuriance of evergreen foliage, like a broad mirror festooned with myrtle and vine. Often, so far away from the course of the boat are the distant shores that one may with difficulty descry the towns and houses which are indicated in the distance. For seventy-five miles and more to the southward the river retains this similitude to a broad and extended lake. Indeed, it seems but a long arm of the sea, the rise and fall of the tide being perceptible even at that distance. Night closes on the journey. During the time you pass through an expanse of the river twelve miles wide and eighteen miles long (Lake George), and when you awake you find the boat in a narrow stream, running beneath the shade-of overhanging vines and palmettos, the waters bearing upon their surface a strange, floating, bright-green vegetation, well described by the popular name water-lettuce. Along the shore acres of broad-leaved water-lilies rise and fall with the rapidly-running waves, which surge along the course of the steamer. Here the stream is exceedingly tortuous, and the greatest care is needed on the part of the pilot lest, in turning the acute agles of low-lying land which project to the right and left like alternating narrow blades, his boat will shoot forward beyond his control and fasten itself amid the tangled boughs of a partially submerged forest. This is the paradise of the sportsman, the home of wild ducks and turkeys, and pelicans, and pink curlews.

At a distance of one hundred and ninety miles from Jacksonville another broad expanse of water is entered—Lake Monroe—five miles wide and twelve miles long. On the shore of this lake the boat lands at Sanford, Orange County, which is the head of navigation for large steamers. Beyond this lake the river again diminishes in depth, and is navigable only for very light-draught boats. The origin of the river is in Lake Washington, amid the marshes of the Everglades, two hundred and fourteen miles farther to the south.

There are but few places on the course of the river that are desirable for invalids, on account of the proximity of swamps and danger from malaria. At Sanford I was somewhat amused to see the proprietor of a prominent hotel, which solicits the patronage of invalids, taken with a severe chill while at the desk receiving his guests.

The best places on the river are Magnolia and Green Cove Spring, twenty-eight and thirty miles south of Jacksonville, and Palatka, seventy-five miles from there, each of which possesses superior hotel accommodations, and is subject but little, if at all, to malaria during the winter season.

Gainesville, some forty miles west of Palatka on the line of the Transit Railway, is one of the best locations in the State. It is situated on comparatively high land for Florida, is surrounded by pine-woods, and free from malaria—but, other than as a health resort, has no attractions.

Jacksonville, the center of trade activity, eighteen miles from the mouth of the St. John's, is a city of considerable enterprise. The comforts and conveniences of a Northern city can be obtained there in greater degree than anywhere else in the State. It has, however, in addition, some of the injurious influences which pertain to large cities. There is more danger of typho-malarial diseases and intestinal troubles.

St. Augustine—twenty-five miles south of the mouth of the St. John's, on the coast—that old Spanish town which rests so tranquilly by the sea, looking out over the broad waves of the Atlantic, which roll across from the mother-land, is a most interesting place to the voyager. Its quaint houses, built in the Spanish fashion, from the coquina or imperfectly-formed limestone which is quarried on the beach; its narrow and winding streets, which one may almost cross with a single stride; its old fort, dating from 1696, when Spanish power still ruled a large portion of the world, and Florida was one of the least of its possessions—these, and the many legends which linger around the only moss-covered ruins in America, are the attractions of the place. Long before Jacksonville or any settlement on the St. John's River existed, St. Augustine was noted for its salubrious climate. It is now known, however, that its exposed position on the coast, subjecting it to the whims of every wild northeaster, make it unfitted for very sensitive invalids, though still a favorite resort for several wealthy New York gentlemen of yachting proclivities, who have villas there—and also for those of youthful fervor who cling to romance and sentiment.

  1. Dr. J. C. Kenworthy.
  2. "Meteorology," by Sir John F. W. Herschel, Edinburgh, 1861, p. 193.
  3. The temperature of these places is from the "Smithsonian Temperature Tables." The relative humidity is calculated from data of five years 1877-1881 inclusive supplied the writer by the Chief Signal-Officer, General W. B. Hazen, Washington, D. C. The absolute humidity is calculated from "Table X" of "Smithsonian Meteorological Tables," by Guyot, giving weight of vapor in grains troy, contained in a cubic foot of saturated air between 0° and 105° Fahr.
  4. The temperature of the surface-water of the Gulf of Mexico, off Key West, in May, was 7712° Fahr., as determined by the United States Coast Survey, 1857, p. 102.

    The average temperature of the St. John's River, at Jacksonville, to the depth of eighteen feet, determined by daily observations by Sergeant J. W. Smith, United States Signal Service, from September, 1881, to March, 1882, is 70° Fahr.

  5. The population of Jacksonville, including suburbs, is considerably above this, but the mortality statistics are limited to a district the population of which is as stated.