Wright. — Chemistri/ of Flesh Foods. 15 



Chemical Experiment No. 6. — Showing Acidity of Fats — continued. 



Bacteriological Experiments. 



It is now recognized that tlie flesh of healthy animals is free from 

 bacteria, but as soon as death ensues, if no measures are taken to guard 

 against bacterial infection, the flesh becomes a suitable field for bacterial 

 invasion and growth. 



As bacteria are almost universally present in the air, it is expected that 

 on the surface of meat there will be found bacteria, and that if the meat 

 is allowed to remain unprotected the bacteria will spread to the interior 

 of the meat. 



The method of the experiments was to remove portions of the meat from 

 the surface and the interior, using every precaution to prevent contami- 

 nation. The portions of meat so removed were dropped into flasks contain- 

 ing sterilized bouillon, which were carefully sealed and incubated at 21° C. 

 for fourteen days. These were examined from time to time, and a note 

 made when growth was found to have occurred. In the event of no growth 

 at the end of fourteen days, the contents of the flask were contaminated 

 artificially to sliow that bacterial growth was possible. 



Bacteriological Experiment No. 1 was carried out with fresh lamb and 

 mutton, to determine how soon the bacteria, which were invariably present 

 on the exterior of the meat, could penetrate to the interior of the meat, 

 which was previously found to be free from bacterial infection. It wa& 

 found that in from five days in the case of lamb to seven days in the case 

 of mutton bacteria could invade the interior of meat when exposed to 

 ordinary temperatures. 



Bacteriological Experiment No. 2 was carried out to verify the absence 

 of bacterial infection in the meat used for Chemical Experiment No. 5, 

 where the ripening of meat was allowed to proceed in the kiiown absence 

 of bacteria. In no case did bacteria develop, although it was shown that 

 after contamination the bouillon was a suitable medium for bacterial 

 development. 



Bacteriological Experiment No. 3 was carried out to ascertain whether 

 bacterial growth and invasion of the interior of the meat proceeded during 

 cold storage. 



In every case it was found that the surface of the meat, even after 160 

 days of cold storage, was infected with bacteria, but that the interior was- 



