SEWAGE CONTAMINATION OF OYSTER BEDS. 931 
with a single exception, proved to be growths of micrococci. One of 
these, a yellowish growth, was a large sarcina, forming regular packets 
of cells, and coinciding closely with the description given for Sarcina 
subjflava. A flesh-colored growth proved to be J/icrococcus carneus. 
M. concentricus was also observed in these plates. The single bacillus 
type found was Ps. fluorescens. 
Plates inoculated with the juice of these oysters, on the other hand, 
exhibited a considerable difference in appearance from those already 
described. An abundant growth developed in this series of plates, 
and in some cases the gelatin was entirely liquefied by the large num- 
bers of bacteria present, so that only very small quantities of this juice 
could be added to the culture tubes. The predominant forms found 
in these plates were bacilli. Only three species of micrococci were 
observed. Jf. luteus and Af. carneus were found in 5 out of 20 plates. 
A large micrococcus, forming a thick white layer on agar and agree- 
ing closely with J/. simplex, was found in two plates. Ten species of 
bacillus tpye were distinguished, perhaps the most frequently observed 
form being Ps. fluorescens, which was found in 80 per cent of the 
samples examined. A nonliquefying fluorescent bacillus, probably 
B. rugosus, was found in 9 plates. For the rest, L. /émosus was found 
in 11 plates out of the 20 examined; a large granular bacterium which 
grew into long anthrax-like chains and formed small oval spores, 
Bact. maritimum, in 7; B. vulgatus in 5; B. sublanatus in 4; B. cireu- 
lans in 7; B. cuticularis in 8, and B. cyanogens in 2 plates of the 20 
examined. Most of the organisms liquefy gelatin rapidly, so that the 
plates are pitted with shallow crater-like depressions in two days. 
The same organisms were also found ina set of gelatin plates made 
from water samples obtained from this locality at high tide. 
The Kickemuit River oyster bed furnished the next supply of oysters 
used in this analysis, full-grown specimens dredged in about 16 feet 
of water; 30 oysters from these layings were obtained and examined 
in the fall of 1900. The stomach content of 20 of these, samples of 
the juice of 15, and portions of the intestinal content of 10 were inoc- 
ulated into the usual gelatin medium. The plates inoculated from the 
juice of these oysters did not develop growth different in many respects 
from that obtained from the Greenwich Bay oysters. Liquefying 
organisms were most numerous, often destroying the plates in a few 
days. Four species of micrococci were observed in this series: J/. 
auriantiaca, M. concentricus, M. luteus, and Sar. lutea. 
M. auriantiaca was found in 20 per cent of the samples examined; 
M. luteus, M. concentricus, and Sar. lutea a less number of times. 
The ‘bacillus forms observed most frequently were those common in 
water; B. subtilis, B. limosus, and Ps. fluorescens were most plen- 
tiful. Bact. maritimum and B. vulgatus were also found in these 
samples. 
