10 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS, 



the box and at the same time hold the metal box firmly in place. 

 On the top of each wooden upright piece a button keeps the box 

 from slipping up and down should the package be turned bottom 

 upward. Cracked ice and sawdust, or ice alone, is packed in the 

 air space for refrigeration. The lid of the box may be left unlocked 

 to permit re-icing during long shipments, provided the inner box 

 is sealed. 



The earlier samples of water and shellfish were shipped to the 

 laboratory in ice-cream freezers during moderately warm weather, 

 but when the weather was extremely cold no ice was used in shipping 

 short distances. Both water and shellfish samples were protected 

 from melting ice during shipment by being placed in water-tight 

 containers surrounded by ice. 



Deep-water samples were taken by the aid of a heavy cylindrical 

 jacket made of lead, arranged in such a manner as to hold the bottle 

 in place, at the same time permitting the stopper to be lifted a given 

 distance by a string or wire without removing it the full distance 

 out of the neck of the bottle. A rubber band attached to each side 

 of the clamp grasping the stopper caused it to fly back in place 

 when the attached string was released. Surface samples were 

 taken as near 1 'foot under surface as was practicable. 



Oysters and clams were fished from their beds either by tongs or 

 by dredges, each sample being properly labeled for future identifi- 

 cation. Generally about 12 to 15 medium-sized oysters or 6 clams 

 constituted a sample. 



PREPARATION OF SAMPLES OF SHELLFISH. 



(1) Clean shells by thorough scrubbing with a brush in running 

 tap water, rinse in sterile water, dry between folds of a sterile towel. 



(2) Cleanse the hands thoroughly after scrubbing the oyster 

 shells, select five cleaned oysters, slightly flame the lips of each shell 

 before opening, and open with a sterile oyster knife, observing 

 aseptic precautions, keeping deep shell downward. Either draw off 

 liquor with sterile pipette or decant into sterile flasks. 



A summary of the chief advantages of examining the whole oyster 

 and liquor is given by Houston 33 as follows: 



(1) It is a definite quantitative method, succeeded by qualitative records. 



(2) It gives the average volume of the whole contents of the oyster shell. 



(3) It yields results based on collective examinations of ten oysters. 



(4) It includes the examination of the entire contents of the shell, not of a fraction 



either of the liquor or the gastric or intestinal juice, or the mixture of these 

 liquids. 



(5) The results can be stated as number of bacteria either per oyster or per cubic 



centimeter of oyster. 



According to the observations of the writer the total quantity of 

 oyster liquor and body range from about 8 to 20 cc, averaging 



