ON INTESTINAL ORGANISMS. 



57 



To 200 c.c. of samples of water prepared as stated, and contained 

 in sterile Erlenmeyer flasks, were added two 3-mm. loops of the 

 fresh bouillon cultures of typhoid and colon bacilli respectively. 

 Counting the duplicate experiments provided for, we thus had a 

 series of 1 2 flasks, 6 of them containing typhoid bacilli, and 6 colon 

 bacilli. 



For determining the number of organisms, 1 c.c. of the respective 

 solutions was transferred directly to a Petri dish by means of a 

 sterile i-c.c. pipet, and to this was added 10 c.c. of Heyden's 

 nutrient agar, which had been kept at a temperature of 40 ° C. for 

 some time. Three separate plates of the water in each of the 12 

 flasks was made immediately upon the addition of the cultures, and 

 both the plates and the flasks were kept at a temperature of 35 ° 



Table I. — Experiments with Bacillus coll. 



Water Without Copper Foil. 



Triple 

 Distilled 

 Water 



At time of add- 

 ing culture. 

 At end of 4 



hours. 

 At end of 8 



hours. 

 At end of 24 



hours. 

 At end of 48 



hours. 

 At end of 6 



days. 

 At end of 14 



days. 

 At end of 21 



days. 

 At end of 28 



days. 

 At end of 53 



days. 

 At end of 60 



days. 

 At end of 83 



days. 

 At end of 90 



days. 

 At end of 1 30' 



days. 



Filtered 



Tap 

 Water. 



7,746 11,246 



7,655 '■ 5,075 



7,735 ! 3,"5 

 1,000,000 1,000,000 

 1,200,000 1,600,000 

 1,200,000 1,000,000 



Tap 

 Water. 



8,283 



7,665 



7,000 



1,500,000 



2,000,000 



1,200,000 



Water With Copper Foil. 



Triple 

 Distilled 

 Water. 



,866 



No or- 

 ganisms. 



1,060,000 910,000 2,245,000 



700,000 462,000 650,000 



700,600 462,446 



602,000 456,000 



! 583,200 421,000 



215,600 128,766 



208,133 

 289,333 



48,433 

 146,543 



649,666 

 693,000 



687,333 

 206,950 

 147,000 

 225,400 



4,410 



No or- 

 ganisms. 



Tap 



6,790 



No or- 

 ganisms. 



1 The nutrient medium used in the plates made at the end of 130 days was agar 

 having an acidity of 0.5 percent. 



