220 PATHOGENIC BACTERIA IN MILK 



we have seen, 22 per cent, of the milks examined contained 

 the bacillus. In Croydon 164 milks were examined, with the 

 result that 6-y per cent, were found to contain B. tuberculosis} 

 In 1897 Obermiiller found 38 per cent, of the milks examined 

 in Berlin contained the tubercle bacillus ; in the same year 

 Rabinowitsch found the bacillus in 28 per cent.; and in 1898 

 Petri, also in Berlin milk, found it in 14 per cent.. As early as 

 1884 H. Martin found 33 per cent, of the milks examined in Paris 

 yielded the tubercle bacillus; in 1893, Sacharbekow found 5 per 

 cent, of St Petersburg milks positive ; and in 1898 Beuge obtained 

 30 per cent, in Halle milks. Numerous other records might be 

 quoted, but the above will amply suffice to illustrate the occurrence 

 of this organism in milk as it is actually placed on the market. 



The tubercle bacillus in butter.— The products of milk also 

 become infected, as we have already pointed out. Greening found 

 that 47 per cent, of butter samples apparently contained tubercle 

 bacilli. Again, Obermiiller found virulent tubercle bacilli in each 

 of fourteen samples of butter, while Rabinowitsch, in eighty samples, 

 found no tubercle bacilli, but organisms similar in appearance in 

 28-7 per cent. On another occasion she found 13 per cent, of butters 

 examined contained the tubercle bacillus. Petri found 32 per cent, 

 of true tubercle bacilli in butter. Korn found the true tubercle 

 bacillus in 23 per cent, of market butters in Freiburg. Hormann 

 and Morgenroth melted butter at 37°, and injected 4 to 5 c.c. 

 into each of four guinea-pigs intraperitoneally. In some experi- 

 ments the butter was centrifugalised after melting, and the fat-free 

 sediment injected, with the object of introducing the infection as 

 free as possible from fat. With each sample four guinea-pigs were 

 injected direct with the fluid butter, four with a portion which had 

 been incubated at 37° for twenty-four hours, and two with the 

 sediment obtained on centrifugalising water in which the butterj 

 had been washed. Of ten samples treated in this way three gavel 

 entirely negative results, three disclosed the tubercular organism! 

 which could be cultivated from the organs of the test animals,] 

 and four gave results which were ambiguous. Organisms, sirnilai 

 to the tubercle bacillus, were recognised in several cases. So fai 

 as the experiments went, they showed no advantage in centri-| 

 fugalising the butter or in incubating it before injection. Glycerim 

 agar failed in every instance as a culture medium, blood serui 

 with 5 per cent, glycerine being the only medium which turned out 

 to be satisfactory, and the growth on this was in every case small^ 

 * Report on the Health of Croydon (Dr Richards), 1901, p. 753. 



