MICROORGANISMS IN WATER 



2S9 



AVERACE AKNUALDEATH RATE FKOH 1Y7IKIID FEVER PER 100.000 OFTHE POPULATION. 

 1912 I iO 28 30 .40 SO 60 



- An instructive contrast between Altona and Hamburg before the latter filtered 

 its water, having learnt its lesson from a sharp outbreak of cholera. 



*SMTTERED CASES OF CHOLERA. 



AITOWA 



HAMBUR6. 



POPUUTION: 600.000 



CHOLERA CASES: ir.OOO 



- DEATHS: 8.600 



ALTONA : 



^ WATER FILTERED 



HAMBURG: 



Water umfiltered 



Fig. T.10.-;— {After G. E. Armstrong.) 



