The soil in its relation to disease : a report of observations / by T. R. Lewis, and D. D. Cunningham.

  • Lewis, T. R. (Timothy Richards), 1841-1886.
Date:
1875
Catalogue details

Licence: Public Domain Mark

Credit: The soil in its relation to disease : a report of observations / by T. R. Lewis, and D. D. Cunningham. Source: Wellcome Collection.

Provider: This material has been provided by Royal College of Physicians, London. The original may be consulted at Royal College of Physicians, London.

    19/28 (page 13)
    The only point of interest which calls for special remark in regard to this com- parison is the demonstration which it affords of the occurrence of local variations in the amount of carbonic acid present in the soil of localities in close proximity to one another, and to all appearance extremely similar in their nature. The sites of observation were not iiig^nfference inp?oces^soccurring more than 50 yards apart, and were both situated m the sou of adjacent localities. similar and corresponding distances from the walls of one and the same building. The processes going on in the soil in the two places must have differed materially, in degree at all events, if not in kind ; and if such processes occurring in the soil have any influence on health, it is obvious that people inhabiting one end of the building must have been exposed to different hygienic conditions from those living at the other end. Such an observation is of special interest in connection with the extremely marked, and frequently apparently inexplicable, localisation in the distribu- tion of cholera within narrow limits—even within the limits of individual buildings. (d)— Comparison of the amount of Carbonic Acid present in the Soil with the Temperature of the Soil at similar depths.—(Diagram III.) On consulting the tables and diagrams it becomes at once clearly evident Amounts of carbonic acid not that the amount of carbonic acid present in the determined by soil-temperature. soil a£ yari0US times is not determined by the mere coincident temperature of the soil. Maximum temperature coincides with minimum amount of carbonic acid at one period, and with a very large amount of carbonic acid at another. The lines of temperature neither direct- ly nor conversely correspond with those of carbonic acid. There is, however, one curious phenomenon which comes out very distinctly during the period over which the observations extend, and this is that the periods of maximum difference in the quantities of carbonic acid in the two layers of soil coincide with the periods of maximum difference of temperature in these layers. The minimum difference in the quantities of carbonic acid occurred in August and September, and during the same period the minimum difference of tempera- ture also occurred. The two periods of maximum difference between the amounts of carbonic acid in the two layers of soil were first in December, January and February, and second in May; at both of these periods maxi- mum differences in temperature were also present. Whether this be a mere coincidence we do not feel prepared to say, but it may be poin’ed out that if the conditions of temperature be in any way causatively related to the differences between the quantities of carbonic acid present in the layers of soil, the essential element is the difference of temperature, not the absolute temperature of either layer individually. The coincidence of maximum differ- ences of temperature and carbonic acid occurred at one time when the tempera- ture of the lower layer of soil exceeded that of the upper one, and at'another when the reverse relation prevailed. (c)—Comparison of the amount of Carbonic Acid present in the Soil with the Atmospheric Temperature.—(Diagram III.) No clear relation of any kind can be observed to exist between the atmos- pheric temperature and the amount of carbonic acid Absence of connection between at- 1 , . .. . . n , , mospheric temperature and amount present in the sou — periods of extreme elevation of carbonic acid in tbe soil. 1 . . ..... and depression of the latter occurring comcident- ly with conditions of temperature showing no corresponding changes. (/j—Comparison of the amount of Carbonic Acid in the Soil with the Rain- fall.—(Diagram, III.) In this case a general coincidence of conditions appears very distinctly, Connection of carbonic acid in the puncipal penods of iain-fall coinciding with the soil with rain-faii; the principal periods of elevation in amount of car- bonic acid, and the main periods of depression in the latter coinciding with periods of drought. This general coincidence is, however, much closer and more marked in reference to the carbonic acid in the upper than to that in D