39 



which just previously of an emulsion of B. typhosus so much 

 had been added that each cubic centimetre contained 

 2,470,000 B. typhosus (for method, see previous experiment). 



The oysters were kept in this typhoid-infected water for 

 24 hours, and after retaining for analysis one of the smallest 

 oysters (No. 1), the rest were taken out, well rinsed on outer 

 surface, and separated into two lots, each lot containing 

 about the same proportion of " small " and " full-sized " 

 oysters. Lot 1 (" wet oysters ") was then transferred to fresh 

 clean tub and covered with 2000 c.c. sterile sea water. The 

 other lot (" dry oysters ") was laid out on a plate and placed 

 in cool chamber. The small oyster No. 1 yielded on analysis 

 95,800 B. typhosus and 900 B. coli communis. It has to be 

 remembered that this oyster was a very small one, the shell 

 not larger than the size of a penny. In this case one- 

 hundredth part of the minced body of the oyster yielded on 

 a Drigalski plate 958 colonies of B. typhosus and 9 colonies 

 of B. coli communis. 



It is not necessary to detail all the procedure in the analysis 

 of the sea water and the two lots of these oysters, since they 

 were the same as were described in the previous experiments, 

 and we can at .once proceed to give the summary of the 

 results : 



The sterile sea water as also the tub for the wet oysters 

 were changed every day. 



Sea water immediately after infection 2,470,000 B.typh.per Ic.c. 



of tub, 24 hours,, 1,530,000 



,, 1 day after change 13,180 ,, 



2 days 10,580 



A Of) 



35 * 33 33 35 AV 5) 33 



6 per T V c.c. 



33 33 * 35 53 53 ^ 3J 53 



It will be seen from this that one day after having been 

 changed the sea water still contained 13,180 B. typhosus per 

 1 c.c., which could only have been derived from the interior 

 of the oysters, since the sea water had been sterile when 

 added to the infected oysters, and the tub well brushed and 



