474 THE POPULAR SCIENCE MONTHLY. 



sometimes exaggerated there was a time when many believed that it 

 would remove all sickness, and it would not be surprising if the reac- 

 tion against this exaggeration should lead to an undue depreciation 

 but it is an established fact that every city that has completed a well- 

 flushed system of sewerage in connection with house-drainage has 

 gained in health, and that its death-rate, especially from diseases con- 

 nected with the soil, has diminished. I mention the reports, on the 

 frequency of typhus before and after sewerage, of John Simon for the 

 English cities, of Yarrentrapp for Frankfort-on-the-Main, and of Lievin 

 for Dantzic. We hear, indeed, that the general prevalence of typhus 

 has ceased, and that its disappearance in these cities is wrongly placed 

 to the credit of costly sanitary works ; but the coincidence must be 

 full of significance to every unprejudiced person that the disappear- 

 ance of typhus in different cities has not taken place simultaneously 

 and in the same degree, but has generally begun with the intix>duction 

 of water-works and sewers. In Hamburg, for instance, improvement 

 began to be evident in 1848, and in Dantzic in 1872. If now we con- 

 clude that the genius epidemicus has undergone a change, this genius 

 must have manifested a wicked partiality for Hamburg and a devilish 

 maliciousness toward Dantzic, to have kept the latter city so long in 

 his claws. Soyka recently communicated to the meeting of the Ger- 

 man Sanitary Union a statistical report respecting the typhus in Mu- 

 nich, in which the influence of sewerage was set forth in the plainest 

 manner, perhaps more plainly than it has been done in any other case. 

 It is known by long experience in this city that abdominal typhus, 

 when it is epidemic, prefers certain quarters, including sewered and 

 unsewered parts alike, and that it spares certain quarters, including 

 sewered and unsewered parts alike ; showing that the disease is gener- 

 ally connected with the local situation, not with the existence or non- 

 existence of sewers. Now, Soyka has found that between 1866 and 

 1880 typhus diminished in the unsewered and the old and badly sew- 

 ered parts of the city, in round numbers, only ten per cent, in the 

 favorably situated and well-sewered parts about twenty per cent, in 

 the unfavorably situated but well-sewered parts about forty per cent'. 

 That the wonderful result in the last case was accomplished by sewer- 

 age becomes obvious when it is considered that in it an otherwise fer- 

 tile typhus-field, in which more seed was to be destroyed, had to be 

 dealt with. Such facts make it very hard for the opponents of sewer- 

 age to continue to deny its hygienic advantages. 



A well-regulated system of sewerage with adequate flushing not 

 only promotes the removal of much filth, but also effects a great dilu- 

 tion of all soluble and floating dirt, and contributes toward rendei'ing 

 it harmless and effecting its complete destruction. The opponents of 

 sewerage insist that it is impossible to construct a perfectly tight 

 system of sewers. This is not essential ; it is enough to reduce the 

 quantity of impurities penetrating into the soil, so far as they are of 



