538 Journal of Agricultural Research voi.vi, N0.14 



gauze. The hindquarter was next wrapped in dry cheesecloth and heavy 

 paper and transported at once to the laboratory by motor truck, the trip 

 requiring less than an hour. 



METHOD OF TAKING SAMPLES 



To obtain relatively large and aseptic samples of meat such as were 

 used in these experiments is not an easy matter, and extreme care had to 

 be taken to prevent bacterial contamination. After several failures 

 samples free from bacteria were obtained in the following manner: At the 

 laboratory the hindquarter was transferred at once to a special inocu- 

 lating room about 10 feet square. The walls and floors of this room had 

 been previously washed with the mercuric-chlorid solution. A special 

 canopy ceiling consisting of cheesecloth tacked on a light frame had been 

 placed in the room at the height of about 10 feet, and this was sprayed 

 with a solution of liquor cresolis compositus just before taking the sam- 

 ples. The floor and walls were also sprayed at the same time with the 

 compound cresol solution and were damp while the samples were being 

 taken, the idea being to have the floor, walls, and ceiling moist, so that 

 any floating dust particles would stick to them. 



For taking the samples a number of large, heavy-bladed scalpels and 

 long dissecting forceps were used ; these had been sterilized and wrapped 

 in cotton. Large plugs of meat, approximating 3-inch to 4-inch cubes, 

 were cut from the muscular tissue, avoiding connective tissue and fat as 

 much as possible. These plugs, weighing from 274 to 512 gm., the aver- 

 age being 377 gm., were immediately transferred to sterile crystallizing 

 dishes fitted with deep glass covers. In cutting out the plugs the line of 

 incision was first thoroughly seared with a hot spatula. Then a light cut 

 was made through the outside to the depth of about 0.5 cm. and the knife 

 used for the incision was laid aside. A second sterile knife was then used 

 for continuing the deeper incision. This was done in order not to carry 

 in any of the mercuric-chlorid solution which might have adhered to the 

 outside. The outer or exposed portions of the meat samples were always 

 trimmed away to the depth of at least half an inch in order to eliminate 

 those portions which had come in contact with the bichlorid gauze. 

 Thirty-three samples were taken in this manner. 



The dishes containing the samples were weighed, the covers sealed 

 with adhesive tape, and over the tape were placed strips of tin foil. This 

 was done for the double purpose of preventing evaporation and the 

 possibility of bacterial contamination from the outside. 



BACTERIOLOGICAL CONTROL OF SAMPLES 



The dishes containing the meat samples were placed in the incubator 

 and carefully watched from day to day for evidence of bacterial growth. 



Twenty-four of the thirty-three samples showed bacterial contamina- 

 tion upon incubation — that is, visible bacterial growths developed on 



