--------+----+-------+-------+-------+-------+-------+-----+-----+------ 11 a.m.| 1 | 121| 184| 285| liquid| ...|1:2.4|1:...| ... 12 noon| 1 | 115| 171| 223| 380| 392| 1.9|1:3.2|1:3.2 2 p.m.| 1 | 109| 152| 221| 362| 375| 2.0| 3.3| 3.4 4 p.m.| 1 | 121| 175| 251| 410| 415| 2.1| 3.4| 3.4 10 a.m.| 2 | 6,200| 8,500| 8,800| 8,900| liquid| 1.4| 1.4| ... 10 a.m.| 3 |425,000|650,000|670,000| liquid| ...| 1.5| ...| ... --------+----+-------+-------+-------+-------+-------+-----+-----+------ ORIGINAL SAMPLE. UNTREATED AND UNDILUTED --------+----+-------+-------+-------+-------+-------+-----+-----+------ 11 a.m.| 1 | 915| 1,410| 1,630| 2,150| 3,200|1:2.2|1:2.8|1:3.5 --------+----+-------+-------+-------+-------+-------+-----+-----+------ [A] Results are bacteria per c.cm. Table XVI shows the effect of a concentration of 1.0 p.p.m. of chlorine; the hypochlorite at this concentration acted almost entirely as a germicide or disinfectant. TABLE XVI.[A]--EFFECT OF CHLORINE AS A DISINFECTANT AVAILABLE CHLORINE 1.0 P.P.M. ---------------+------------------------------ PLATED. | INCUBATION PERIOD, DAYS. ---------+-----+-----+-----+-----+-----+------ Time. |Day. | 2 | 3 | 4 | 5 | 6 ---------+-----+-----+-----+-----+-----+------ 11 a.m. | 1 | 2| 5| 7| 8| 10 12 noon | 1 | 1| 1| 2| 2| 4 2 p.m. | 1 | 0| 0| 0| 2| 2 4 p.m. | 1 | 1| 2| 2| 6| 6 10 a.m. | 2 | 0| 0| 0| 1| .. 10 a.m. | 3 | 0| 0| 0| ..| .. 10 a.m. | 4 | 5| 13| 16| ..| .. 10 a.m. | 5 | 79| 166| ..| ..| .. Untreated| | | | | | water | .. | 915|1,410|1,680|2,150|3,200 ---------+-----+-----+-----+-----+-----+------ [A] Results are bacteria per c.cm. Table XV shows a recovery of the anabolic functions after treatment with 0.1 p.p.m. of chlorine but since this was obtained by plating on such a suitable medium as nutrient gelatine, it is probable that reproduction in water having a low organic content would be still further diminished. This is indicated by the results obtained. There is no evidence of any marked difference in the resistance of ordinary water bacteria to chlorine and these are the first to be affected by the added germicide. The common intestinal organisms are also very susceptible to destruction by chlorine and there is considerable evidence that _B. Coli_ is slightly more susceptible than many of the vegetative forms usually found in water. The specific organisms causing the water-borne diseases, typhoid fever and cholera, are, on the average, not more resistant than _B. coli_.