232 REPORT OF THE COMMISSIONER OF FISHERIES. 



Sixty per cent of the plates inoculated with material from the 

 stomachs of Kickemuit River oysters remained sterile. Two of the 8 

 plates that showed growth in three days contained large numbers of 

 colonies of /'y. Jf^iorescens, M. lutexis^ M. flavus^ M. carneus^ and a 

 species of sarcina (not described in this paper). A nonliquefying 

 fluorescent bacillus was also observed in a number of cases, forming 

 regular glistening colonies that look like small drops of water on the 

 surface of the gelatin, which takes on a pale green fluorescence. This 

 organism is described on the chart as bacillus No. 11. 



The 10 plates inoculated from the intestinal content of these speci- 

 mens developed abundant growth in two days. Liquefying bacilli 

 were present in great numbers. Again Ps. fluorescens was met with 

 in a large percentage of plates examined; also a small motile liquefy- 

 ing organism, bacillus No. 6, was found in 6 of the 10 plates. Col- 

 onies liquefy slowly and form bluish-white depressions in the gelatin, 

 some reaching a diameter of 5 mm. in four days. Microscopically 

 they have a granular center around which is a clear hyaline area that 

 usuallj^ has a distinctly wavy margin. B}^ transmitted light they 

 resemble a bluish star with a dark white center surrounded b}^ a thin, 

 irregular bluish growth. Agar, gelatin, and broth cultures of this 

 organism assume a characteristic brown color after about tw^o or three 

 weeks' growth at room temperature. Colonies of B. mesentericus 

 {\?ir\Qty fiiscus)^ B. tivM'dis^ Bad. mmntlnimn, and of the nonliquefy- 

 ing fluorescent bacillus No. 11, already referred to, were found in these 

 plates. M. flavus and M. auriantiaca were met with on several 

 occasions. 



A more extended stud}" of the flora of the oysters' intestines was 

 made on several lots of specimens obtained from Wickford Harbor in 

 the fall of 1902. In this series of experiments material from the 

 intestinal content of 100 oj^sters was inoculated into the usual gelatin 

 medium. This anal3^sis was begun October 1-1, and from that date 

 specimens were obtained twice a week for over two months. Arrange- 

 ments were made with the parties controlling the Wickford o3^ster 

 beds, by which 03\sters caught Tuesday and Thursday mornings were 

 shipped to Providence and received in the laboratory the same day 

 they were taken from the water. They were then immediately opened 

 and cultures taken from the intestines. 



Plates made from Wickfo)"d oysters as a rule developed a large 

 number of liquefying colonies, and though the organisms most fre- 

 quently observed were rod forms, colonies of micrococci were occa- 

 sionally met Avith. M. flavus was found in 5 per cent of the plates 

 examined; also cultures of M. luteus and M. auriantiaca were taken 

 from colonies developing on 3 of these plates. Another coccus form 

 more frequently met with in this examination is referred to on the 



