622 A MANUAL OF BACTERIOLOGY 



of the baker's oven. Cut bread forms a good nidus for the develop- 

 ment of pathogenic organisms. 



The Bacillus prodigiosus may grow upon various food-stuffs, and 

 give rise to suspicion of foul play. L. Parkes x describes cases of 

 diarrhoea which he suggests were caused by this organism. 



Butter contains from two to forty-seven millions of micro- 

 organisms per gramme. Tubercle bacilli have been found in butter, 

 and the comma bacillus artificially introduced survives for over a 

 month. " Acid-fast " non-pathogenic forms also occur (p. 340). 



For the isolation of the tubercle bacillus from butter and cheese 

 the only certain method is by inoculation. Butter may be melted 

 and allowed to stand in the incubator at 37 C. for some days, and 

 the sediment inoculated. As this involves the multiplication of 

 septic organisms, it is preferable to centrifuge the melted butter, 

 keeping it melted during the process, and to inoculate the sediment 

 immediately. 



Clothing, etc. Attempts have been made to examine clothing, 

 bedding, flock, etc., by bacteriological methods for filth contamina- 

 tion, but without much success. 



1 Brit. Med. Journ., 1905, vol. ii, 1330. 



