ABSTRACTS 107 



words, whether these plants could be depended upon to improve the 

 water if it came from a contaminated well. 



Experiments conducted with small quantities of water (2 to 3 liters) 

 held in steel chambers at varying degrees of pressure up to 100 pounds 

 per square inch, and at the temperature of a warm room, showed that 

 the contained bacteria increased very rapidly and to an enormous 

 extent. B. coli was not affected by the pressure. 



When similar samples were held at the temperature of an ice box, 

 but otherwise under the same conditions, the growth was marked but 

 slow. When water held under similar conditions in the ice chest was 

 partially renewed at intervals of 24 hours by pouring out half the water 

 and putting in fresh, the number of bacteria appeared to remain nearly 

 constant. 



An examination of several plants in actual operation showed that 

 the water in these tanks remained practically constant so far as their 

 bacterial content was concerned. 



The Bacterial Content of Market Oysters. Fred Berry. 



Eight samples of shell oysters and twenty-one samples of shucked 

 oysters, collected from eighteen different retail markets in Chicago 

 were examined according to the methods recommended by the Committee 

 on Standard Methods of Shell-fish Examination. The first sample 

 was collected October 13 and the last April 27. Additional tests were 

 made to determine whether the use of- the combined shell liquor of 

 fifteen oysters, as recommended by Smith, would necessitate a different 

 interpretation from that based on the analysis of five individual oysters, 

 as recommended by the Standard Methods Committee. A few samples 

 of shucked oysters were re-tested after storing in the ice-box for forty- 

 eight hours to determine the character of the bacteria which multi- 

 plied most rapidly under such conditions. 



Of the eight samples of shell oysters, three contained an excessive 

 number of B. coli. These were collected October 13, October 23, and 

 March 2, and had a score of 41,140, and 120, respectively. The other 

 five samples were collected in February and four of these had a score 

 of 0, one a score of 23, and the other a score of 5. The lowest count 

 on the shell oysters was 2600 on a sample collected February 8, and the 

 highest was 7,740,000 bacteria per cubic centuneter on a sample col- 

 lected March 2nd. 



Of the twenty-one samples of shucked oysters, none was free from 

 B. coli. The minimum was 1 and the maximum 40,000 B. coli per 

 cubic centimeter of oyster liquor. Fifteen of the twenty-one samples 

 contained 100 or more B. coli per cubic centimeter. Eight of these 

 fifteen contained 1000 or more B. coli per cubic centimeter. The 

 count on shucked oysters varied from a minimum of 140,000 to a maxi- 

 mum of 34,000,000 bacteria per cubic centimeter of oyster liquor. 



These results may be summarized as follows: 



1. The shell oysters purchased at Chicago during February contained 

 fewer bacteria than those purchased in October and March. 



