56 



WET OYSTERS. 



Oyster 1 after 24 hrs. in infected water, 46,200 B. coliper oyster. 

 ,,3 ,,1 day change . . . 2325 

 5 ,,2 days' ... 1305 



**/* )) 5J 



jj 7 3 ,, ,, ... 216 ,, ,, 



9 A 11 



JJ * )J )J ... A i. ,, ,, 



117 1 ft 



)) - 1 A )> ' 5J 3} ... IO ,, ,j 



13 8 ... per | oyster. 



DRY OYSTERS. 



Oyster 2 1 day dry . . 8575 B. coli communis per oyster. 



4 2 days dry . . 7940 



63 . . 5796 



84 . . 2625 



Starting, then, with 230,000 B. coli communis per 1 c.c., 

 the sea water had diminished them in 24 hours down to 

 177,000; but then we should not forget that there have been 

 11 oysters in the water ; taking all these 11 oysters as having 

 contained, or rather having withdrawn from the water, 

 the same number of B. coli communis, i.e., 11 times 46,200, 

 there would have been on account of this withdrawal only 

 an insignificant number (half a million) removed from the 

 460,000,000 originally added to the water. From this it 

 follows that the number of B. coli communis had actually 

 been reduced by the sea water from the original 460,000,000 

 to 353,500,000 (177,000 X 2000 c.c., minus 500,000 for the 

 eleven oysters). This reduction does not, therefore, compare 

 with that observed in connection with the B. typhosus, and 

 this coincides with what is known as to the greater hardiness 

 and greater resistance of the B. coli communis over the 

 B. typhosus. We notice, however, that in the oysters kept 

 in clean sea water, frequently changed, the reduction of the 

 B. coli communis was rapid and marked. By three days' 

 changes the number of B. coli communis had been brought 

 down to 216 (from the original 46,200), and after eight days' 

 changes no B. coli communis could be discovered any longer. 



