470 THE POPULAR SCIENCE MONTHLY. 



observed in Munich in 1873 and 1874, can be explained only by refer- 

 ence to the conditions of the soil as to moisture. The epidemic began 

 at the end of an abnormally dry July, prevailed with extraordinary 

 violence till the beginning of August, became stationary about two 

 weeks afterward, and seemed wholly to have disappeared at the end 

 of October, only to break out anew with greater violence in Novem- 

 ber after a long spell of dry weather, and continued till the end of 

 April, 1874. The city of Augsburg, nine miles from Munich, suffered 

 more severely in j)roportion than that city in 1874, but was quite free 

 from cholera in 1873, notwithstanding many cases were introduced. 

 It had thirty per cent more rain in that year than Munich. 



I can not go further into the consideration of these circumstances ; 

 I only cite them as evidence of the influence of moisture in the soil so 

 far as it is measurable by the proportion of ground-water present. 

 We are more nearly concerned with the relation of the soil to the 

 water which we apply to our own use, which we draw from wells and 

 springs, to water as a vehicle conveying matters out from the soil. 

 When typhus or cholera rages epidemically in any place, two parties 

 immediately set up a contention as to whether the epidemic influence 

 proceeds from the water or the air. It must be admitted henceforth 

 that either is possible, that a so-called sickly soil can impart its noxious 

 properties equally to the water and to the air it contains, but it may 

 also be that only one of these ways is possible as to certain matters 

 and lower organisms. Observation and experiment must decide upon 

 that. Most physicians have hitherto considered that infection was 

 probably most directly conveyed through the water, and the so-called 

 drinking-water theory has been developed from this view. It ' has, 

 however, been ascertained that the best known infectious agent in the 

 soil, the Bacillus mcdaHce, which Klebs and Tommasi-Crudelli have 

 discovered and studied in the Roman fever-districts, can not live with- 

 out air. These investigators found that the malarial poison was not 

 communicated to the water that stood over a richly malarious mud. 

 Tommasi says, in his latest work on the Roman malaria and the 

 ancient drainage of the Roman hills, that "the Bacillus malarice is pre- 

 eminently an air-living organism." Among the conditions favorable 

 to its propagation in a malarial soil which need not be a swamp-soil 

 Tommasi specifies a temperature of about 20 C. (68 Fahr.), a mod- 

 erate degree of steady moisture, and the direct action of the ox} r gen of 

 the air on all parts of the mass. He says further, " The lack of one of 

 these conditions is enough to cause a suspension of the development 

 of the spores and of the increase of the malarial ferment." If any 

 one, however, believes that this organism must also remain inoperative 

 when it passes into our blood because that is a fluid, he should be 

 reminded that it makes a great difference whether we put such organ- 

 ism-;, taken from their airy nests in a moist soil, into cold water, or into 

 warm blood where air is supplied to them from the corpuscles. 



