IO0 S .] 



ON INTESTINAL ORGANISMS. 



63 



of organisms in those solutions containing bouillon between the 

 first 4 and 24 hours, there was after this a marked increase in 

 growth. This increase in development would appear to begin after 

 the last inhibiting traces of copper are removed, either by precipi- 

 tation in the organisms or by the bouillon. 



Other experiments which we conducted showed that there was a 

 difference in the persistence of the typhoid organisms depending 

 upon whether the cultures added to the water were 2 4 -hour or 14- 

 day bouillon cultures, as seen in the following table. 



Table VII. — Experiments with Cultures of Bacillus typhi of 

 Different Ages. 



The figures in Table VII, show that the older cultures of the 

 typhoid organisms were most resistant in the tap water, and that 

 they survive over 7 days in Berkefeld-filtered water, the 24-hour 

 cultures usually being destroyed in about 4 hours. 



Table VIII.- 



-experiments on tap water with copper foil and copper 

 Sulphate. 



Tap Water without 



Copper Foil or 



Copper Sulphate. 



Berkefeld 

 Filtered 

 Water. 



Tap 

 Water 



with 



Copper 



Foil. 



Tap Water with 

 Copper Sulphate. 



1 Part to 1 Part 

 100,000 1,000,000 



At time of adding copper 

 foil or copper sulphate. 



On drawing tap water or 

 before filtering. 



After filtering. 



At end of 2 hours. 



days. 



39,000 



32,666 

 21,300 

 40,900 

 41,000 

 68,933 



39,ooo 



8,233 



46,800 

 666 



27,133 



I 35,666 



■ 29,266 



20,516 



! 9,866 



61,466 609,900 



87,100(500,200 



n,ooo 395,300 33,600 

 '343,700 



9,500 

 7,766 

 10,200 



13,333 



102,200 



1 ?3j 



3°o 



66 



200 



300 



3,633 

 185,000 

 211,760 



8,233 



1,833 

 1,300 

 2,233 

 1,166 

 112,300 



97,l5o 

 134,000 



