A PINK YEAST CAUSING SPOILAGE IN OYSTERS. 5 



Table 1 shows that the pink yeast is widely distributed through- 

 out the oyster house and the adjacent structures, and can be found 

 on the decks of the boats, 73.9 per cent of the locations examined 

 giving positive results. At the oyster house where the investigation 

 was made the oysters are hoisted from the decks of tlie boats in tubs, 

 then dumped into deep wooden wheelbarrows and carried back along 

 the runway to be emptied into the bins within the house. Starting 

 at the bins and the opening benches, the pink yeast was found to be 

 rather abundantly distributed on the sides and floors of the bins. 

 The bins first examined in 1916 had not been used since the pre- 

 ceding April, so that the dust from several summer months had 

 accumulated in them. This dust contained large numbers of the 

 yeasts. Attention was next directed to the wheelbarrows in which 

 the oysters are carried, swabbing-s from the inside of two of which 

 showed that the pink yeasts are to be found there also. Swabbings 

 made from the tubs in which the oysters are hoisted also showed the 

 presence of the yeasts. Going still further back in the search, an 

 examination of the swabbings made of the decks of the boats showed 

 pink yeasts. Oysters from the decks examined at this time showed 

 no yeasts. In examining the oysters from the decks of the boats, the 

 oyster meats within the shell were analyzed, but the outsides of the 

 oyster shells were examined in the sample taken from the bin within 

 the house. These results show that the oyster house itself and the 

 utensils on the premises are, at least, sources of the infection. 



IN OYSTERS. 



To ascertain whether or not the oysters already contained the 

 yeasts when taken from the waters of the bay, further analyses were 

 made. 



Method of Analysis. 



Visits to the docks were made at the time when the steamers were 

 to arrive, and samples were obtained before the work of unloading 

 had begun. A representative sample of 15 or 20 oysters was taken 

 from the middle of the pile on the deck, and transported to the labor- 

 atory in a cardboard box. The oysters were scrubbed thoroughly 

 with a stiff brush in warm water and soap. They were then opened 

 aseptically, and 3 oysters placed in a sterile jar with their liquor. In 

 opening the oysters the knife was sterilized with flaming alcohol, 

 and the edge of the oyster shell was passed through the flame before 

 opening. The opened oysters in the jar were vigorously shaken 50 

 times and dilutions made of the liquor. The proper dilutions ^ were 

 plated on dextrose agar and examined as already described. 



1 0.1 cc. and 0.01 cc. were found to be adequate. 



