BACTERIOLOGY OF REDDENED COD. 57 



face removed with a sterilized knife, and the pieces placed in large, 

 covered glass dishes. Inoculations of the coccus alone at room tem- 

 perature developed spots about a millimeter in diameter in from two 

 to three weeks, then increased very slowly. In about five to six weeks 

 reddening developed, usually at places on the fish other than the 

 points of inoculation, and after this the fish reddened fairly rapidly. 



Fish inoculated with the bacillus developed clear, jelly-like colonies 

 from one-half to one and a half millimeters in diameter in from two 

 to three weeks. Sometimes growth would cease, or there might be a 

 slight development. Then, as with the fish inoculated with the 

 coccus, reddening developed, usually on other parts, and proceeded 

 in a similar manner. 



When the coccus and bacillus were used together, at first there de- 

 veloped a colony having a red center and a clear, jelly-like envelope, 

 after which a general reddening developed, sometimes at the point of 

 inoculation, sometimes at other points. 



Development from inoculation with the mold was very uncertain. 

 On some of the fish many small white dry-looking colonies formed; 

 n other pieces no development took place. The time of development 

 ras practically the same as for the coccus and bacillus. 



MICROSCOPIC EXAMINATION. 



Examination of the early stage of the reddening when a small 

 olony only had developed at the point of inoculation gave the coccus 

 done, or the coccus with but a few bacilli, and possibly a few of 

 ;he oidia of the mold ; as the reddening increased, however, the num- 

 >er of the bacilli and oidia increased. A similar condition was 

 lound when the bacilli were used for inoculation. The transparent 

 olony consisted of the bacilli with many free spores. After redden- 

 ng developed the coccus was always present, though the bacillus 

 aright predominate. The mold was usually present also. 



The colonies of the mold, even in the early stages, nearly always 

 lad cocci and bacilli present. 



The pieces of fish used for control in the foregoing tests remained 

 ! ree from reddening in most cases. In those in which reddening 

 id occur the first appearance was from three to four weeks later 

 han the general reddening on the inoculated pieces. 



From the results of these tests it was decided that the pieces of fish 

 tv-ere not sterile when inoculated and that the organisms must pene- 

 rate farther into the flesh than was supposed, in order to account for 

 he presence of the organism or organisms not used in the inoculation 

 nd also the slower general reddening. A different method was 

 hen employed. The thickest pieces of fish obtainable were cut into 

 )ieces 2 to 3 inches square with a sterilized knife, used while hot, and 

 vere then sliced into halves, so as to get a new surface at the greatest 



