Vol. k, No. 1, pp. 160-200, 1953) reported non- 

 sterile Nansen bottles produced almost the same 

 counts as sterile samples and since other 

 determinations were made from these same water 

 samples. By the end of the trip to Panama it 

 was evident that the bacterial counts in water 

 collected in the plastic samplers were much 

 higher than those obtained in sterile J-Z 

 samplers. Several direct comparisons were 

 made at the same place, depth, and time and 

 10^ to 10^ more cells were taken from the 

 plastic samplers. The resulting contamination 

 in plastic samplers apparently developed from 

 a bacterial film on the sides of samplers due 

 to their constant use. This was concluded 

 after observing the gradual increase in bac- 

 terial numbers after each use. These figures 

 are not presented. 



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