In 1867-68 sporadic cases occurred at Little Rock, Ark., and in the former year in Madison co., N.Y., thirty-three cases were reported.9 In Chicago, between February and April, 1872, Dr. Davis reported forty cases observed in his own practice in seventy-two days. In the same year the disease occurred at Elizabethtown, Ky.,10 and at Louisville, Ky., in December of the same year. It existed in Michigan between 1868 and 1874, but only in the latter year epidemically, and not to a very great extent.
9 Trans. Med. Soc. State of N.Y., 1868, p. 251.
10 Richmond and Louisville Journ., Nov., 1872, p. 555.
Of later occurrences of the disease the following may be mentioned: Several cases were reported in London in 1867, 1871, 1876, and 1878.11 In 1870 four cases were observed in Providence, R.I.12 In 1882 cases were met with in Boston, New York, Philadelphia, Pittsburg, Western Ohio, Indianapolis, Detroit, Louisville, Memphis, New Orleans, Richmond, Milwaukee, St. Louis, Salt Lake City, San Francisco, etc., but in none of these places did the disease become epidemic.
11 Times and Gazette, July, 1867, pp. 58, 59; Nov., 1867, p. 511; Guy's Hospital Rep., 3d Ser., xvii. 440; St. Bart's Reports, xii. 267; Times and Gaz., Aug., 1878, p. 167.
12 Boston M. and S. Jour., Oct., 1870, p. 261.
ETIOLOGY.—Epidemic meningitis has occurred in Europe and America in every portion of the temperate zone, but its greatest prevalence and mortality have undoubtedly been in the northern rather than in the southern portions of that region. One of its most interesting features consists in its appearing simultaneously at points very remote from one another and having no connection with each other save through the atmosphere. Of this statement several illustrations have already been presented. Another peculiarity of the disease consists in its occurring with hardly any relation to external natural conditions or to those of its victims. It affects localities as diverse as possible in their geological, meteorological, and sanitary states, the rich and the poor, the old and the young, and both sexes, and (as it is certainly not in a strict sense contagious) its rise and spread must necessarily be attributed to some occult cause pervading the atmosphere.
It is evident that the prevalence of the disease has some relation to meteorological agencies, for not only is it greater, on the whole, in cold than in warm climates, but it is also greater in cold than in warm seasons. Thus, if we examine the epidemics in Europe and America we shall find that they almost invariably were most severe in the winter and spring. Yet the rule presents several exceptions on both continents. In France, out of 216 local epidemics, more than one-fourth took place during the warm months of the year, and in Sweden the proportion was about the same. It is evident, therefore, that cold is not an essential cause of the disease. Among the problems that remain unsolved in regard to this disease none is more obscure than the apparent immunity of Russia from its ravages, although the climate seems adapted to favor it, and the domestic habits of no people are fitter to intensify it if individual conditions entered into the etiology of the disease; but, in truth, no such causes are related to epidemic meningitis. Localities of every sort, high and low, dry and moist, those saturated with marsh miasmata and those fanned by pure mountain-breezes, have been alike visited by this disease. It has passed by large cities reeking with all the corruptions of a soil saturated with ordure and populations begrimed with filth, as Vienna, Berlin, Paris, London, and New York, to devastate clean and salubrious villages and the families of substantial farmers inhabiting isolated spots.
By far the greatest number of the subjects of epidemic meningitis are young persons. In Sweden, according to Hirsch, of 1267 fatal cases of the disease, 889 occurred in persons under fifteen years of age, 328 between sixteen and forty years, and 50 in persons of forty years and upward. In 1866, in the Kronach district (Germany), of 115 cases, 75 occurred under the seventh year, 22 between the seventh and twelfth years, and 10 between the thirteenth and twentieth years (Schweitzer). During 1865 a local outbreak of the disease in Bavaria affected 53 persons, of whom 22 were children under ten years of age, 18 between ten and twenty years, and 11 between twenty and thirty years. Under the fifth year few were attacked (Orth). Dr. J. L. Smith13 found that, according to the reports of the Board of Health of the city of New York, out of 975 cases, 771 occurred in persons under fifteen years of age, the greatest number for any quiquennial period being 336 in children under five years. Of the 469 deaths occurring in this epidemic, 216 were of children under five years of age, and the next largest number for an equal period was 99, which represented the deaths between the ages of five and ten years. Of adults or persons beyond the age of twenty, the whole number was but 39. The peculiar liability to the disease of the young recruits in the French army has already been alluded to. The proportion of male victims to this affection is rather larger than that of females in the civil population, but in France especially the excess was greatly on the side of males, owing to the prevalence of the disease in the army. In other places, as in Sweden and Germany, the number of deaths among females equalled, or even exceeded, that of males, and in Leipsic the garrison remained exempt while the disease prevailed among the citizens. In 1847 a fatal epidemic of it affected the second regiment of the Mississippi Rifles, and was entirely confined to that corps (Love). During the Civil War of the United States the disease affected particular corps or regiments in the South or in the North, yet it never became epidemic in the army, even when the disease prevailed among the adjacent civil population.
13 Amer. Jour. of Med. Sci., Oct., 1873, p. 320.