XI, B. 2 Gabel: Examinations of Swimming Pools 69 



Table A. — Approximate dimensions of the swimm.ing pools tested in Manila. 



Pool. 



Length. 



Width. 



Depth. 



Capacity. 



Meters. 



Feet. 



Meters. 



Feet. 



Meters. 



Feet. 



Cubic 

 meters. 



Gallons. 



I. 



18. S 

 18.3 

 18.3 



60 

 60 

 60 



6.0 

 6.5 

 7.2 



20 

 18 

 23.5 



1.2 to 2.4 

 1.2 to 2.4 

 1.2 to 2.7 



4 to 8 

 4 to 8 

 4 to 9 



200 

 200 

 226 



52,400 

 52, 400 

 59,400 



II 



III.. 





The city water supply was used by all. This is a river water, 

 which is chlorinated by adding about 0.5 part of available chlo- 

 rine per million parts of water after passing through a reser- 

 voir. The temperatures of the pools were reasonably constant 

 during the period of examination, varying only from one to two 

 degrees from 28.5°C. The water was changed each week on 

 Sunday, except during the week of November 8 to 13, when the 

 water of the previous week continued in use. The disinfectant 

 was applied by first dissolving it in a pail of water and then 

 scattering the solution over the water in the pool. When the 

 bleaching powder was thus properly distributed, no irritant 

 effect on the eyes of bathers or other objectionable features to 

 its use were detected. At pools I and II it was customary 

 simply to drain off the old water and put in the new, while at 

 pool III the emptied tank was thoroughly cleaned before being 

 refilled. The advantage of the latter process in reducing the 

 original bacterial count is strikingly shown in Table I, August 

 30, where the counts of the uncleaned pools after refilling aver- 

 aged 68,000 bacteria per cubic centimeter as against 3,600 for 

 the cleaned pool. 



METHODS USED AND RESULTS OBTAINED 



The one hundred eighty-nine samples of the water tested 

 were collected in 50 cubic centimeter, sterile, cotton-stoppered 

 bottles at about 8 o'clock in the morning. At the pool a 

 sample bottle was fastened to a stick, the plug was signed and 

 removed, and the specimen of water was obtained by thrusting 

 the bottle about 1 meter below the surface. These bottles were 

 carried in a covered metallic box, to protect them from dust, 

 rain, and sunlight. The samples were usually plated within 

 forty minutes of the time they were taken. 



In this work, unless otherwise stated, the methods and rec- 

 ommendations of the committee on standard methods of water 

 analysis of the American Public Health Association (1912) were 



