assertion, because they had always boasted of their immunity from cholera; they replied: "What are 500 deaths out of a population of 400,000? It is absurd to call that an epidemic!" Of course, it would not be right to speak of an epidemic of all Lyons, but most assuredly there existed an epidemic in a part of it. The higher-lying districts had enjoyed their usual immunity in 1854. In the times of cholera which followed 1854 Lyons preserved its freedom. In what respect did 1854 differ from all other years? In nothing but in the fact of its greater dryness. I availed myself of the observations of the meteorological station, and found that in this year the amount of evaporation was greater than the rainfall. Observations on the subsoil water were not to be obtained, but there was the register of the condition of the Rhone dating as far back as 1826. From 1826 to 1854 there was no lower register so lasting as that of the last year. These facts were sufficient to lead me to understand how the lower-lying parts of Lyons could be brought into a condition susceptible of an epidemic of cholera by the partial or total removal of the influence of the Rhône.
That too much as well as too little water in the soil is unfavorable to cholera is vouched for by a large mass of facts. As I watched the cholera in Bavaria during 1854 I was surprised to find that the marshy districts, where, as a rule, the poorest dwelt, were exempt from epidemics. The great Donau bog, which lies between Neuburg and Ingolstadt, was surrounded by the epidemic, but the disease did not enter the villages on the fen. On the Freisinger moors an epidemic occurred at Halbergmoos. On going thither the affected houses were found to stand on a tongue of land composed of quartz, which tongue reached inward on the moor. Reinhard had proved the same thing for Saxony. The northern part of Saxony, which lies on the Spree, is a highly malarious district. For the eleventh time that cholera visited Saxony it shunned this region of fever. I will not say that cholera can not be epidemic on a fen, but I do believe that when such an occurrence takes place we ought to ask ourselves what relation it may have with the state of moisture of the soil. The theory on the soil and subsoil water requires that a knowledge should be obtained of what takes place in and over the soil on the outbreak and on the cessation of cholera. It requires, as Port has said, a continuous record of facts. That cholera should very seldom be met with in the neighborhood of and on mountains is also in harmony with the disposition of cholera in respect of time; so that, as the frequency of cholera in these regions diminishes, the rainfall increases; the weather and cholera are equally capricious. Towns among mountains which are refuges for fugitives from cholera are but seldom situated on a soil which in and of itself would exclude cholera. Salzburg and Innsbruck have, for example, never yet been visited by cholera. Further, in 1866, these towns escaped, although a considerable influx took place from the seat of war where cholera raged. Salzburg, but still more Innsbruck, stands on
