a 
at different times from all parts of the clam within the mant'e. In several cases 
a culture was made from a little of the shell liquor withdrawn through the pedal 
orifice by means of a sterile pipette. No attempt was made to associate an 
ioslated organism with the part of the clam in which it was found. — 
To simulate factory conditions, a few clams were washed as described above 
and allowed to stand at room temperature (about 20°C) for 18 hours before 
further steps were taken. Others were treated similarly and left 48 hours at 
room temperature before being opened. In both cases the clams were found 
to be still alive. 
Clam peptone broth and beef peptone broth were both used for first cultures 
in every case. Good growth was obtained in both media. In many instances, 
it appeared earlier in the clam broth and was more luxuriant. After growth 
for twenty-four hours at room temperature, plate cultures were made from each 
tube, both.in clam peptone agar and beef peptone gelatin. These plates were 
examined as soon as growth appeared, usually after from 14 to 18 hours. Plating 
was done in the late afternoon, the plates as a rule showing growth the next 
morning. Most of the organisms liquified gelatin rapidly, hence it was necessary 
to deal with gelatin plates first. Colonies were carefully examined and from 
each one chosen as representative of a new type, an agar stab, an agar slant and 
a smear for microscopic examination were made. Seventy-six cultures were 
thus obtained during four weeks beginning July 24, 1920. Agar stab cultures 
of each were kept until the opening of the autumn session at McGill University, 
when laboratory facilities permitted further investigation. 
MEDIA USED. 
1. ISOLATION MEDIA. 
Clam peptone broth and Clam peptone agar. - 
These were made according to directions given by Sadler’ in his paper on 
“The Bacteriology of Swelled Canned Sardines.”’ 
Beef peptone broth. 
Distilled water. 
Liebig’s meat extract, 0.5 per cent. 
Difco peptone, 1.0 per cent. 
Sodium chloride, 0.5 per cent. ; 
Beef peptone gelatin. 
Beef peptone broth with 12 per cent. of Difco gelatin. 
2. MEDIA FOR DETERMINING THE PRODUCTION OF HYDROGEN SULPHIDE. 
(a) Lead Carbonate gelatin (Beijerinck). 
Beef peptone gelatin+lead carbonate 0.1 per cent. 
(b) Peptone-lead acetate solution (Pake). 
This medium was prepared according to the following directions: Emulsify 
30 g. peptone with 200 cc. tap water at 60°C. Wash into a litre flask with 80 cc. 
tap water. Add 5 g. sodium chloride and 3 g. sodium phosphate. Heat at 
100° for half an hour. Filter through paper. Tube. To each tube of 10 cc. add 
4 
