The above tables give the meteorology, the first that of the three summer months, and the second that of the summer as a unit compared with the same periods of last year and with the average of thirty years. The investigation of the condition of the atmosphere during the last months is of greater than usual interest, because within that time the great epidemic of this century has again made its appearance among us, making it the duty of the meteorologist to investigate any possible connection of the atmospheric conditions with the spreading of the cholera, or any influence the former may have exercised on the latter. I am aware that this question is not a new one, and I know as well that very different solutions have been given-some more specious than others, but none to me quite convincing. I do not expect to solve the difficulties; I only propose to add to the stock of knowledge by giving the results of careful observations. The tables show that June was in every way an average month. The atmospheric pressure was a little below the mean, but the temperature and the quantity of rain were almost equal to the average; the number of fair days a little less, and the number of rainy ones and of thunder-storms a little more than usual. The range of temperature was much lower than we often observe it, for it was neither as warm nor as cool as it frequently is in June. July was also an average month as regards atmospheric pressure and quantity of rain, but the temperature was 2.7 degrees higher than the mean temperature of the month; and this was owing not so much to unusually elevated degrees of heat as to constant high temperature from the fourth to the end of the month, during which period the thermometer rarely fell below 70, and almost daily rose to 90, though seldom over 95 degrees, while a temperature of 98 to 100 is not rare with us in July. The quantity of rain was a little below the average, while the number of days on which it rained, the cloudiness, the relative humidity, and the number of thunderstorms, were greater. Heat and humidity combined began to tell on the sanitary condition of the inhabitants; and bilious diarrhœas, and dysentery, together with remittent and intermittent fevers, made their appearance among our until then unusually healthy population; sporadic cases of cholera-morbus began to show themselves-not, however, any more than we see every summer under similar circumstances. While July was warmer, August proved to be much cooler than this month usually is in our climate. Its mean temperature was fully two degrees below the average, while the highest temperature of the summer also occurred in this mouth. The atmospheric pressure was a little below the average; the humidity and cloudiness were much less, and the evaporation greater, than is usual in August; the quantity of rain was also greater. This seeming anomaly, however, is easily explained if we take into consideration that by far the largest quantity of rain (three and a quarter inches) fell on the evening of the last day of the month, which fall of rain rather belongs to the month of September, initiating the uncommonly wet season of that month. Otherwise, August had only five rains, of which only one (on the 12th) was of any importAfter July 21st there was in fact no rain (with the exception of a slight sprinkle on August 7th) until August 13th, while the July heat continued almost without intermission until then, and culminated on the day before (August 12th), reaching a point above 100 degrees. The second half of the month was characterized by dry, clear, and unusually cool weather, with a prevalence of north-easterly winds. During the first week of the month the same class of diseases prevailed which were noticed in July. Cases of cholera began to multiply until, after the first week of the month, it manifested itself as an epidemic, which increased in extent and in intensity until the last week of August, when it began to abate. ance. The summer, as a whole, was an average one in atmospheric pressure, temperature, evaporation, relative humidity, and quantity of rain; we had more thunder-storms than usual ( as many as last year), and fewer fair days; the winds were more variable, and not so predominantly from the south-east as is common in our summers. As I have said above, the weather during the greater part of July was warm and moist, with a prevalence of easterly and south-easterly winds. July 16th to the 21st we had daily rains, mostly accompanied by thunder-storms, and the heaviest on the 19th. After the 21st the weather became more settled, clear, and dry, and quite hot, and continued so for three weeks, until August 12th-at first with north-easterly, afterwards with north-easterly and south-easterly, winds prevailing. From July 21st to August 1st the temperature never fell below 70 degrees at sunrise, nor below 90 in the warmest part of the day. In the following eleven days of August the atmosphere cooled off somewhat, so that on the morning of the 5th the thermometer indicated only 60 degrees, while on that day and on the 9th it scarcely reached 83 degrees in the afternoon. The heat soon rose again until, on the 12th (the warmest day of the summer), it exceeded 100 degrees; a violent thunder-storm and rain followed in the evening of that day. A period of delightful, clear, cool, and bracing weather succeeded, until the last day of the month, during which only two very light showers scarcely moistened the surface of the parched soil. The thermometer ranged in the morning mostly between 50 and 60 degrees, and in the early afternoon between 70 and 80; only in the three first and the four last days of this period it rose above 80, and solely on the 31st over 90 degrees. With the evening of August 31st a spell of wet weather set in, quite unprecedented in this season in our climate, which lasted until September 25th. During those twenty-six days, only eight were without measurable rain, though on some of them a dark and misty atmosphere made it worse than rain. During all this time, embracing almost three months, the barometer showed no marked variations, but was, as is usual in this season with us, remarkably quiet and steady. From July to the middle of August it was rather high; from the middle to the end of August, somewhat lower than usual; and during September higher again, as is commonly the case in that month. We can, then, distinguish four well-marked periods in these three months: (1) A warm and moist period from July 4th to the 21st; (2) a hot and dry period from July 22d to August 11th, succeeded by two rainy days, the 12th and 13th, which formed the transition to (3) the period of cool, clear, and dry weather, from August 14th to the 30th; and (4) a cool and very wet period, from August 31st to September 25th. Now let us see how cholera appeared during these four periods: During the first period, of warm and moist (I might almost say tropical) weather, so favorable to the generation of such diseases, we had only isolated cases of sporadic cholera-morbus; during the second period, of hot and dry weather, it gradually but slowly increased, and assumed the epidemic form; in the third period, of cool, clear, and dry weatherhealthy, bracing, and recuperative, as it ought to have been-the epidemic raged the worst, but abated suddenly towards the end of the month; during the fourth period, of cool and wet weather, it at first increased again, but then rapidly decreased, and approached, it is believed, its termination. What, then, had the atmospheric influence to do with the advent, the spread, and the cessation of the epidemic? Evidently very little; their effects were only secondary in so far as wet and cool weather predisposed to bowel complaints; and thus, it is believed, the sudden change of August 31st, and the succeeding cool weather, may have induced the recrudescence of the epidemic just at that time. But we must admit that the delightful weather of the middle and latter part of August can in no way be connected with the rapid increase of the cholera during most of its continuance. The meteorological observations, therefore, give only negative results in regard to the march of this epidemic; and atmospheric conditions, evidently, have only a minor influence on it. Experience has, however, proven that in winter the cholera has always disappeared, or, at least, has become greatly lessened. It is a disease of warm weather, which comes to us from warmer climates. The cholera epidemics of 1849, 1850, 1851, 1852, 1854, and 1855, all agree in the great regularity of their course. They began or increased in April, augmented rapidly in May, reached their acme in June or July, and decreased still more rapidly in August, and generally died out in September or October. I thought I had discovered in this six-times-repeated regular course a stable law, according to which the epidemic increased with the, to it, most congenial condition of our atmosphere in the fore part of summer-the wet, sultry, hot weather of June and part of July, when we see cases of sporadic cholera in every year-and very abruptly left us with the advent of hot and dry weather, under the prevalence of atmospheric conditions which produce typical forms of disease, billious remittents and intermittents. I am not now convinced that I was wrong in that position, though our present epidemic commenced when those of the years mentioned above abated. The experience of this year only proves that cholera may also appear late in the summer and fall. It does not invalidate the theory that the fore-summer is with us the season most congenial to its full and fatal development. It may be added that it was in the month of August, in the year 1832, that cholera for the first time appeared in St. Louis in an epidemic form; that it ceased during winter, and prevailed again in the following summer of 1833. I recollect having seen several violent cases in June of that year. If it does at all revisit our city next season, it is almost certain that June will be the month when it will be most prevalent and most pernicious. I refrain from following up the subject of cholera and the laws of its propagation any further, because foreign to the subject of meteorology, but must be permitted to say one more word about the drinking-water that is used in our city. Contrary to an officially-promulgated opinion which condemns our river or hydrant water and recommends the use of cistern and well water, it is my own and other physicians' experience that it is much safer to make use of our river water than to drink well water. I have no experience about cistern water, but presume that in the city it to a great extent shares the bad qualities of well water, though it lacks its hardness. Both kinds of water are liable to be impregnated with the organic impurities accumulating in a large city from a thousand sources, even besides gutters, privies, and sewers, which percolate through the soil, especially where it is not composed of the solid diluvial clay of our hills, but of the porous soil of our bottom lands forming the lower part of our city, or, still worse, of the indiscriminate fillings up of many former ravines, valleys, or sinkholes. Our river water, distributed through our water-works, impure as it is, is certainly healthier than either well or cistern water. It is extensively used in almost every family, and in thousands of families among whom no case of cholera has occurred; while we have known in this visitation, as we did in 1819, many wells in different parts of the city around which cholera cases, as it were, clusteredfor a great part, at least, undoubtedly induced by the use of their water. As our well water will get worse with the increase of the number and the density of our population, a pure and healthy hydrant water becomes every year a more urgent desideratum, and such water can only be furnished us by our great Mississippi. |