32 



B. typhosus, that is, 118 x 200 X 100 = 2,360,000 B. 

 typhosus per 1 c.c., or a little over 2J millions. 



Of tlie oysters having been kept for 24 hours in the 

 infected sea water, one of the " previously wet " lot and one 

 of the " previously dry " lot were taken for analysis, as also a 

 certain amount same manner of dilution as above of the 

 sea water in the tub ; the remaining oysters were all taken 

 out of the infected water keeping the two batches separate 

 well rinsed under the tap on the outside, and transferred to 

 a fresh clean tub with fresh sterile sea water. 



Of the sea water in tub infected with B. typhosus 24 hours 

 previously, 1 c.c. was added to 99 c.c. of sterile water ; of 

 this dilution a Drigalski plate was made with ^ c.c. This 

 plate on incubation yielded 63 colonies of B. typhosus ; this 

 would mean that the infected sea water contained 126,000 

 B. typhosus per 1 c.c. 



Oyster 15 (previously wet), after having been in the 

 infected sea water for 24 hours total amount of fluid of the 

 minced oyster, 3 c.c. ; -^ c.c. of this added to 10 c.c. sterile 

 sea water, and of this dilution took ^ c.c. for one Drigalski 

 plate. This plate yielded a pure culture of B. typhosus 28 

 colonies; this would mean that oyster 15 contained 28 X 3000 

 = 84,000 B. typhosus per oyster. 



Oyster 16 (previously dry), after having been in infected 

 sea water for 24 hours, was opened ; total amount of 

 fluid of the minced oyster, 2 c.c. Of this added -fe c.c. to 

 10 c.c. sterile water ; with -fa c.c. of this dilution made one 

 Drigalski plate, which yielded a pure culture of B. typhosus 

 659 colonies ; this would mean 659 x 2000 = 1,318,000 

 B. typhosus per whole oyster. If we suppose that each of 

 the " previously wet " and the " previously dry " oysters took 

 out of the infected sea water the same number of B. typhosus- 

 as oyster 15 and 16 respectively, we would get 84,000 x 6 

 for the "previously wet" lot and 1,318,000 X 4 for the 

 " previously dry " lot, that is 



504,000 B. typhosus for the six of the former, 

 5,272,000 four of the latter. 



5,776,000 Total. 



