ON INFECTIVITY, ETC., OF THE OYSTER. 667 
37° C., the gelatine at 21°C. to 24°C. As the figures will subsequently 
demonstrate, there is an enormous difference between the number of 
organisms appearing upon the agar incubated at the high temperature and 
the simple or sea-water gelatine incubated at the low temperature. This 
heat method of separation proved quite equal to, if not better than, the 
earbolic acid or potassic iodide methods. 
Experiments.—In the first six cases examined precautions were taken 
to ensure that the oysters were especially fresh ; in the other cases they 
were obtained haphazard from the various shops (see table opposite). 
The number of organisms taken from the stomach of the oyster which 
could survive a temperature of 37°C. were comparatively small. In 
a very large proportion of cases (4 to }) the organism present was 
4. coli in overwhelming numbers, and next in frequency were species 
of Proteus. It will be seen that in one instance at least the organism 
approached in its reactions the typhoid type. We believe that on account 
of the presence of this coli group the identification of the B. typhosus 
would be difficult in nature. We cannot at present state whether the 
coli group found in these experiments indicates sewage contamination, or 
whether we are dealing with a group common in the intestine of the 
oyster and in salt-water. The matter is being investigated by us. But 
as bearing upon the next question we have found that the perfectly fresh 
oyster contains far fewer bacteria, and that the percentage of &. coli is 
much less. 
IV.—The Infection of the Oyster with the B. typhosus and its Removal 
by Washing. 
The following table shows that the typhoid bacillus does not increase 
in the body or in the tissues of the oyster. The figures would rather indi- 
cate, comparing the large number of bacilli present in the water with 
those found in the alimentary tract, that the bacilli perish in the 
intestine. : 
Table showing Number of Organisms present in Stomach after infecting 
Water. 
| ee ae | Organisms | = y 
Oyster! Inoculated | Examined ~°°™®S!) _ present oe present in the 
75 0 alee in Oyster Sess 
Agar | 
1 Aug. 25 | Aug. 26 1,700 almost en- | water in the same case 
| |tirely typhoid) 585,000 per c.c. 
2 ” ” } ” ” 
3 A Aug. 27 7,020 b water in the same case 
| 468,000 per c.c. 
4 i | Ang. 28 7,000 | + | water in the same case 
40,950 on agar, 5,200 
| gelatine 
5 Aug. 26 | Aug. 29 455 7 
6 Aug. 28 | Aug. 30 195 3 | water in the same case 
2,047,500 per c.c. 
7 a Sept. 4 390 4 
8 Aug. 31 Fa 325 pe 
9 3 Sept. 10 455 As 
