July 3. 1916 Effect of Autolysis upon Muscle Crcatin 539 



the moist surface of the samples, which furnished a good culture medium 

 for bacterial growth. These samples were, of course, rejected. The 

 remaining samples showed no visible bacterial growths upon incubation 

 and were removed from the incubator one at a time after intervals ranging 

 from 7 to 100 days and subjected to a bacteriological examination. 



In examining the samples bacteriologically, aerobic and anaerobic 

 cultures were first made from the exuded juice. With sterile instruments 

 bits of muscular tissue were then cut from the outside of the samples 

 and used for cultures. The samples, which, as before stated, consisted 

 of large rectangular pieces approximating 3-inch cubes, were then cut 

 in two with sterile instruments and cultures made by taking bits of the 

 muscular tissue from the center of the samples. A half dozen or more 

 cultures were taken from each sample. Smear preparations were also 

 made from the exuded juice and from the outer and inner portions of 

 the samples and were stained for bacteria. 



Upon bacteriological examination nine of the samples were passed as 

 sterile, there being no growths in any of the cultures made from these 

 samples and the smear preparations being negative. These samples 

 were then subjected to chemical analysis (Table I). 



The fact that so large a proportion of the samples, 24 out of 33, or 

 about 72 per cent, developed bacterial growths goes to show how difficult 

 it is to obtain sterile samples of meat. 



METHODS OP CHEMICAL ANALYSIS 



After having taken the samples of muscular tissue for incubation the 

 remainder of the quarter of beef was placed in cold storage at 33 F. for 

 17 hours, when a composite sample of the lean meat was taken for 

 analysis. Analytical work was started about 24 hours after the slaughter 

 of the animal. 



All samples of meat, both fresh and after incubation, were finely 

 ground, placed in glass jars, tightly sealed, and analytical work was 

 started promptly. 



Moisture and fat determinations were made on all samples. Moisture 

 was determined by drying the material in vacuo over sulphuric acid, and 

 fat was determined in the dry residue by extraction with ether. 



Preparation of extract. — A 0.9 per cent solution of sodium chlorid, 

 saturated with thymol, was used as a solvent. One hundred gm. of the 

 finely ground tissue were macerated in a mortar with the salt solution 

 until a mixture of uniform consistency was obtained. The material 

 was then transferred to a 2 -liter volumetric flask, made to volume with 

 the salt solution, and shaken at intervals during a total extraction period 

 of 24 hours. The mixture was then filtered and analytical work begun 

 immediately. Extractions were made in duplicate and the work was 

 carried on in a refrigerated room at a temperature of about 35 ° F. 



