THE INFLUENCE OF CLIMATE, and OTHER AGENTS, ON THE HUMAN CONSTITUTION, WITH reference tO THE CAUSES AND PREVENTION OF DISEASE, AMONG SEAMEN. By Robert Armstrong, M.D. F.L.S. Deputy Inspector of Hospitals. Pp. 207. London, 1843.

THE substance of the present work was originally prepared by the author in the form of lectures intended to be delivered by him, when in charge of the Naval Hospital at Jamaica, to the various medical officers serving upon that station. He therefore directed attention principally to those subjects likely to be useful to the younger branches of the profession upon their first entering the service, often fresh from the medical schools, thoroughly imbued with the various theories there prevailing, but little if at all acquainted with actual practice. He much wished to caution them against falling into mere careless routine, accepting certain vague terms as sufficient explanations of the phenomena passing around them, to the neglect of the employment of their own powers of observation and thought. Just as he was upon the point of delivering them, however, his appointment to the Naval Hospital at Plymouth, threw him into a different sphere of action, and his notes were put aside. The manuscript having been perused with advantage by several surgeons of ships ordered to the West Indies, Dr. Armstrong has, at their invitation, revised it, and adding some further illustrations, published it in the present form. The first nine chapters relate to various matters connected with the production of disease among seamen, and the hygienic precautions adapted to warding it off; the three last treat of fever in general, and of the yellow fever of Jamaica in particular.

We proceed to extract such portions as we think will interest our readers.

Speaking of the effects of locality and mode of life in inducing varieties in animals, and the human race, the author observes :

"The influence of warm climates is apparent after a few years residence within the tropics: Europeans lose their sanguineous complexions, and acquire the power of resisting the heat better than the new comer. This power of accommodation to circumstances, arises from a corresponding change in the functions of life; and which is usually attributed to the individual having undergone the process of seasoning;-a process of which the most vague opinions seem to be entertained. Even within the limited extent of our own country, we observe the influence of local situation, on comparing the natives of mountainous districts with those in the low country. Among the former, examples of tall individuals are less frequently met with. In the mountaineers, the chest will be found more expanded, and the circulation more vigorous; the muscular system more developed, and the forms harsher. The bilious temperament prevails; and they possess a greater quickness of temper and energy of character.

"This greater development of the respiratory apparatus, seems to result from the physical necessity of situation. In the habit of ascending and descending heights of considerable elevation, and generally breathing a more attenuated atmosphere, the organic apparatus acquires greater capacity and vigour, to enable it to afford the necessary supply of atmospherical oxygen. In level countries, on the other hand, the inhabitants are usually of taller stature: the general conNo. LXXXI. E

tour of the figure is more rounded, from the preponderance of the cellular and adipose tissues. The prevailing temperament is the sanguineous. The chest, when viewed in relation to the size of the body, is less expanded; and they are not so well adapted to undergo fatigue when removed from their native districts. Differences of situation even impress upon the constitution a disposition to particular diseases. Scrofula and consumption, are of more frequent occurrence in the plains and agricultural districts, than in the mountainous parts of the country.

"Let us observe man under other circumstances, as in the crowded districts of a great city, or assembled in masses in our manufacturing towns. Here he is employed in occupations in which dexterity rather than strength, is required; and breathing an impure atmosphere with bad lodging and bad food, the body does not attain its full development, and he is deficient in muscular power. This acquired constitution of body is transmitted to the offspring. His diseases are also modified by his condition; and the constitution has not the same power of reparation in cases of injury or disease. This permanent deterioration in the qualities of the race, has been clearly proved by their disqualifications for those offices, where a certain standard of size and strength is required. It is asserted that men from Spitalfields, and other crowded districts of London, who come forward as candidates for employment in the police force, fall short of the required standard; and that two out of three are rejected, as physically unfit for

service.

"It is observed in some of the worst conditioned of the town districts, that the positive number of the natives of the aboriginal stock continually diminishes, and that the vacancy, as well as the increase, is made up by emigration from healthier districts. In a late enumeration of the settled inhabitants of Westminster, it appeared that not more than one third of them were natives of London. Sir James Mc Grigor, the Director General of the Army Board, stated the fact that a corps levied from the agricultural districts in Wales, or the Northern counties of England, will last longer than one recruited from the manufacturing towns, from Birmingham, Manchester, or near the metropolis. Indeed, so great and permanent is the deterioration, that out of 613 men enlisted, almost all of whom came from Birmingham, and five other neighbouring towns, only 238 were approved for service."*"

Dr. Armstrong observes, that although the animal economy is enabled to regulate its supply of animal heat according to the temperature of the climate or the season, yet some time is requisite to accustom it to any considerable change, and the period of such transition is one of susceptibility to disease. When a large ship of war is commissioned, men are received from all quarters, and comprise not only good and experienced seamen, when they are to be obtained, but also volunteers of every possible variety of constitution, who have frequently been living in a dissipated, profligate, or destitute manner. While the equipment is going on, the working parties in the dock-yard are much exposed to the weather, and catarrhs, febrile and rheumatic attacks, &c. prevail among them; but, as the diet is good and abundant, the ship's company becomes much improved in appearance; while some of them, from the contrast to their former fare, become diseased through repletion. The marines enjoy invariably a higher state of health than the seamen, owing to their restriction to their barracks when on shore, and to their strict order and regularity. When the ship pro

* Poor Law Commissioners Report, 1842.

ceeds to sea, a complete change in the habits of her company ensues. Their diet is salt meat, and their rest disturbed by the alternation of watches; and if stormy weather occurs inflammatory affections soon manifest themselves. If the vessel be destined to the West Indies, a tropical temperature, involving a change of 30° or 40° Fahr., if she sailed in the winter, may be attained in a fortnight.

"On approaching the warmer latitudes, the looks of sailors improve; as the ship glides along before the North-east trade-wind, under a clear and blue tropical sky, days often pass without a sail requiring to be shifted. The temper of the ship's company becomes more cheerful-a greater degree of alacrity is observed in their movements-the skin becomes softer, elastic, and more vascular, with an increase of perspiration,—and they enjoy a superabundance of health, if the phrase may be allowed. In some cases of indisposition, so slight as scarcely to deserve notice, a few ounces of blood have frequently been drawn as an experiment. It exhibited on every occasion, the buffy coat, as we find in other cases of excitement. The crassamentum was firm, and evidently contained a larger proportion of fibrine than usual."

Under these circumstances, the amount and quality of diet allowed continuing the same, much evil would probably result but that Nature, more wise than man, diminishes the assimilative powers. As it is, however, some derangement of the secretions, accompanied by constipation, usually occurs and when disease does appear, it does so usually in the form of inflammatory fever with determination to the head. Boils and prickly heat exert sometimes a useful derivative influence.

"Supposing the East Indies to be the destination of the ship, they pursue their course to the southward, and stretch towards the South American continent. On getting beyond the limits of the South-east trade, they steer to the Southeast, and run into the latitude of 36" or 38° South, where strong westerly winds are found to prevail. In fourteen days, or three weeks, they are again wafted into a cold climate, where the temperature is from 36° to 40° Fahr. and sometimes at the freezing point. The ship continues on this parallel, across the Southern Ocean, for a distance of three or four thousand miles. During this run, nothing is seen to divert the mind; and the countenances of the persons embarked will be found to have undergone a change, and assumed a certain haggard expression. If examined closely, the gums will be seen to have lost their natural red hue, appear shrivelled, and present a whiteness around the roots of the teeth.

"The diseases which now appear, especially if the weather prove wet and cold, are pneumonia, rheumatism, catarrh, and diarrhoea: the accompanying fever being of the low, nervous type. In some cases of slight indisposition, a few ounces of blood were drawn from the arm, rather by way of experiment than from necessity; and it was found to be less florid, and slower in coagulating, than within the tropics; the crassamentum was easily broken down between the fingers, and evidently contained a smaller proportion of fibrine or coagulable lymph. This was observed in seven convicts under 30 years of age, and three soldiers, out of a party of 40, embarked as a guard. The former, although prisoners, were allowed to come on deck before the mainmast when they pleased, and occasionally assisted in working the ship of their own accord. The soldiers did duty as a guard, and were on full rations; while the convicts were on twothirds, or six men had the allowance of four seamen, but they had many comforts in addition.

"If India be the place of destination, on reaching the 70th or 80th degree East Longitude, they direct their course North, and soon get to the South-east trade-wind, which carries them into the Bay of Bengal. Thus, in the short

space of three or four months, the ship's company have experienced two Summers and two Winters.

"Although actual disease may not have appeared during these rapid and extreme changes of climate, it cannot be doubted, that a certain excitability of constitution is generated, which renders the body more susceptible of impression from the ordinary exciting causes of disease." 32.

The author is no believer in the existence and agency of malaria in the production of disease. Its production by the miasmata generated in marshy and other unhealthy districts and places, such as ships' holds, &c., he considers as quite unproved. On two occasions, when fever was prevailing extensively in Batavia, he exposed himself at night purposely to the exhalations proceeding from localities possessing all the physical characteristics said to be favorable to the production of malaria, with impunity. He concludes this part of the subject as follows:

"In the preceding detail, it has been shewn, that we are utterly ignorant of this animo-vegetal poison; that no two authors agree respecting its nature, the circumstances under which it is generated, or its effects upon the human body. How then are we to reconcile these discrepancies with the existence of a material said to be possessed of such tremendous activity-a material of whose existence we have no proof, and of whose physical qualities we have no knowledge? What grounds have we for supposing, that the materials, which are said to give rise to this mysterious and invisible something, should continue for indefinite periods of time in a state of inactivity, as far as regards its production, and yet be undergoing the changes inherent to organized matter all the while? How can such materials let loose for a season exhalations which kindle up the most untractable diseases, and again become dormant ? Such capricious movements among the particles of matter are at variance with the established laws which regulate chemical action in all other cases.

"All our reasonings, therefore, respecting the nature of these miasmata, are founded on an assumption; and consequently want that certainty which constitutes the only sure ground of belief. The existence of this material can only be regarded as an assertion-a species of evidence which is not admissible in the inductive sciences; and until proofs be brought forwards of a very different kind from any yet adduced, we cannot acknowledge, without admitting contradictions and impossibilities, the existence of this vegeto-animal poison. The belief in such a material has an injurious effect, because it tends to suppress all observation and inquiry into the various causes of disease; whereas, by close observation, and the correct application of well-known principles, we shall soon find, that there are many powerful causes operating upon the bodies of men in warm climates; and which are fully sufficient to account for the ravages of disease, without the necessity of calling in the aid of aereal and unsubstantial phantoms." 71.

Among the powerful causes alluded to in the above extract, Dr. Armstrong includes the various meteorological changes in the state of the atmosphere, as evidenced by the varying condition of its electricity, magnetism, and weight. Then again the "sol-lunar influence" should by no means be disregarded. He remarks further:

"These investigations appear to have been entirely neglected or overlooked by medical officers in the public service, yet there is no class of men who have greater opportunities of contributing to scientific knowledge. The state of the atmosphere and the intimate connexion which subsists between it, and the condition of the various functions of life, are of the utmost interest and importance,

both in health and disease; and in this extensive, and yet untrodden field, a rich harvest may be reaped. An account of the temperature of the air night and morning, as inserted in the journal, without reference to other circumstances, is of comparatively little value, and cannot afford data for any practical results. The dryness and humidity, the sudden changes of temperature, and of the electrical condition, should be carefully observed. The radiation of heat in warm climates; the geological structure of the country; and the periods of the accession of diseases, are also objects of the greatest interest, and by common industry and observation, much valuable information may be obtained."

Although we cannot agree with the author in his views respecting the non-existence of malaria, we believe great good must result from directing the attention of medical officers to the various other potent causes of disease, many of which are susceptible of mitigation or removal. Thus the change of habits, diet, &c., on arrival at the ship's destination, the laborious employments then performed aboard her, under exposure to the sun's rays, together with indulgence in spirituous liquors, give rise to much disease. Not only is exposure to a tropical sun a fertile source of mischief, but the variation of temperature is so likewise. Thus the ship's company, while in harbour, is crowded into so small a space that each man has seldom more than 16 inches at his disposal. The temperature of the lower deck has been often observed at 90° or higher, while the air on deck did not exceed 70° or 75°, with a strong breeze loaded with moisture blowing. On coming on deck a slight shiver or chill occurs. "Getting out of bed in a state of profuse perspiration, they will remain in this cold air for a time to cool themselves. On returning to their hammocks, they feel chilled and restless, and some febrile attack succeeds. Many cases of fever, acute rheumatism, pneumonia, and dysentery could be clearly traced to this cause." The great increase of sickness during long-continued hot weather has been frequently remarked; and the statistical report shews this to be the case, not only in the West Indies, but in the East, the Mediterranean stations, &c. Even moderate exposure to the sun, when conjoined with active employment, is highly injurious.

The author considers the changes of temperature, to which the soldier and sailor are exposed in hot climates, have not been sufficiently dwelt upon.

"These changes are greater, it is true, in some months than in others, but they occasionally occur at all seasons. At Port Royal, I have repeatedly observed a reduction of from 15° to 20°, in the space of half an hour. About sun-set, when the sea-breeze had died away, and the air was perfectly calm, a thermometer placed in an open balcony would indicate 86° or 90°. Á strong land breeze charged with moisture, would now come down in strong gusts from the mountains, and reduce the thermometer to 68° or 70°, and sometimes lower. At midnight, and at sunrise, in the morning, the thermometer has often been observed at 70° and 72°: the air was then cool and pleasant, and half an hour's walk along the beach was most invigorating. Between nine and ten o'clock, when the land-wind had subsided, and before the sea-breeze had set in, the thermometer would be from 84° to 90.°

"The duck frocks and trowsers afford a sufficient covering during the day, when the temperature in the shade is from 80° to 86°, and many degrees higher in the sun. In the evening, when the temperature is reduced by the cold landwind saturated with moisture, and consequently its conducting power greatly increased, warmer clothing is absolutely necessary. During calm, clear nights,