SANITARY RELATIONS OF THE SOIL. 33 5 



tality of the people. Formerly, if one asked in Lyons why the city 

 was so happily and so strikingly spared, he would not be referred 

 to the unusual cleanliness and comfortable life of the common people, 

 nor to- the splendid drinking-water, for, before filtered Rhone water 

 was introduced in 1859, this was very bad, but to the air, whose cir- 

 culation through the confluent valleys of the Rhone and the Saone 

 was so lively that it was always master over the imported cholera- 

 poison, and would not let it develop. But if we compare the velocity 

 of the wind as observed at the Lyons meteorological station with that 

 of other places much afflicted with cholera, we shall not find the 

 slightest difference in favor of Lyons. The plain of Languedoc, over 

 which the mistral blows so often, unroofing houses, uprooting trees, 

 and destroying ships in the very harbor of Marseilles, is not seldom 

 visited by epidemic cholera. Later investigations show that nothing 

 is left with which to explain the immunity of Lyons but the condition 

 of its soil. Apart from the size of the city, this immunity is not more 

 striking it is, in fact, not so striking than that, for example, of Ver- 

 sailles, where, notwithstanding a constant daily and hourly communi- 

 cation with Paris, cholera has never broken out in an epidemic form. 

 Decaisne has shown that the condition of the soil only can be regarded 

 as bearing upon the immunity of this place. 



Analogous facts may be found wherever the spread of cholera or 

 typhoid is earnestly investigated. The beautiful city of Salzburg, 

 which is now so hospitably entertaining the Association of Naturalists 

 and Physicians, belongs to the number of fortunate cities that have so 

 far been spared cholera-epidemics, notwithstanding numerous refugees 

 from cholera have collected here when the disease prevailed in Austria 

 and Southern Bavaria ; among whom cases have occurred without the 

 infection passing over to the city. Only in the winter of 1873-74, 

 when a severe outbreak of cholera occurred in the prison establishment 

 at Laufen, did weak signs appear in Salzburg, showing that at least'cer- 

 tain quarters of the city were not absolutely and invariably protected 

 against cholera. So Lyons was made aware once, in 1854, that the 

 whole city was not insusceptible to it. The Lyonnese were not willing 

 to acknowledge this, for they had boasted too much of their immunity ; 

 but they asked, What do a few hundred cases of cholera in fifty years 

 amount to in comparison with the total population (400,000 souls) of 

 the city ? We should not treat the subject in this way, but should 

 rather ask, How many inhabitants has the part of the city which, even 

 if it was only once, had a considerable number of cases of cholera ? 

 and then the reply can not be evaded that the suburb of Guillotiere 

 suffered from a decided cholera-epidemic in 1854. This once-occurring 

 epidemic was associated with an equally rare abnormal drought and 

 a long-continued low stage of water in the Rhone, such as had not 

 been observed since 1826. So Salzburg might at some time be visited 

 with cholera, at least here and there, if the sky should obstinately keep 



