2. Pick off any suspicious orange coloured colonies, plant on sloped agar, and incubate at 20° C. Observe pigment formation. 3. Prepare subcultivations from any suspicious growths upon all the ordinary media, study carefully and investigate their pathogenicity. ~8. Micrococcus Melitensis.~--The milk from an animal infected with M. melitensis usually contains the organisms in large numbers and but few other bacteria. 1. Spread several sets of surface plates upon nutrose agar, each from one loopful of the deposit in tube D^{1} or D^{2}. 2. Spread several sets of surface plates upon nutrose agar, each from one drop of the original milk sample. 3. Incubate aerobically at 37° C. and examine daily up to the end of ten days. 4. Pick off suspicious colonies, examine them microscopically and subcultivate upon nutrose agar in tubes; upon glucose agar and in litmus milk. 5. Test the subsequent growth against the serum of an experimental animal inoculated against M. melitensis to determine its agglutinability. 6. If apparently M. melitensis, inoculate growth from a nutrose agar culture after three days incubation intracranially into the guinea-pig. ICE CREAM. ~Collection of the Sample.~-- 1. Remove the sample from the drum in the ladle or spoon with which the vendor retails the ice cream, and place it at once in a sterile copper capsule, similar to that employed for earth samples (_vide_ page 471). 2. Pack for transmission in the ice-box. 3. On arrival at the laboratory place the copper capsules containing the ice cream in the incubator at 20° C. for fifteen minutes--that is, until at least some of the ice cream has become liquid. ~Qualitative and Quantitative Examination.~--Treat the fluid ice cream as milk and conduct the examination in precisely the same manner as described for milk (_vide_ page 443). EXAMINATION OF CREAM AND BUTTER. ~Collection of the Sample.~--Collect, store, and transmit samples to the laboratory, precisely as is done in the case of ice cream. ~Quantitative.~-- _Apparatus Required_: Sterile test-tube. Sterilised spatula. Water-bath regulated at 42° C. Case of sterile plates. Case of sterile graduated pipettes, 1 c.c. (in hundredths). Tubes of gelatine-agar (+10 reaction). Plate-levelling stand, with its water chamber filled with water at 42° C. METHOD.-- 1. Transfer a few grammes of the sample to a sterile test-tube by means of the sterilised spatula. 2. Place the tube in the water-bath at 42° C. until the contents are liquid. 3. Liquefy eight tubes of gelatine-agar and place them in the water-bath at 42° C, and cool down to that temperature. 4. Inoculate the gelatine-agar tubes with the following quantities of the sample by the help of a sterile pipette graduated to hundredths of a cubic centimetre--viz.,