106 HISTORY AND CAUSE OF THE COCONUT BUD-EOT. 



Bacillus coli was used for comparison iii the second experiment, but 

 not in the first. There appear to be no great differences between 

 these organisms and B. coli. The experiments show in general 

 that in Fischer's mineral solution alone or when KNO3 is added the 

 organism barely clouds; when peptone is added moderate growth 

 results; adding glycerin either with or without KNO3 gives slight 

 growth; when either dextrose or cane sugar, either with or without 

 KNO3 is added poor growth results; when peptone with either dex- 

 trose or glycerm is added moderate growth results. 



From this table it will be observed that the organism can obtain its 

 nitrogen and carbon easily from peptone alone, but somewhat bet- 

 ter when dextrose is present. It can not obtain any nitrogen from 

 KNO3, and carbon from glycerin only with difficulty (p. 75). The 

 organism can obtain carbon only with difficulty from either cane sugar 

 or dextrose alone; undoubtedly some nitrogenous substance, such as 

 peptone with either cane sugar or dextrose is necessaiy for good 

 growth. 



MEDIA WITH MALACHITE GREEN. 



The use of malachite green as a differentiating medium between 

 Bacillus coli and Bacillus typliosus has been recommended by Loeff- 

 ler, according to Kiralyfi,^ who has also tried it but without success. 

 In view of the variable results obtamed by Kiralyfi the effect of mala- 

 clute green as mhibitory to Bacillus coli is not taken here as a diag- 

 nostic character. As a matter of fact, notwithstanding that Kiralyfi 

 in some experiments found that a 0.02 per cent solution of malachite 

 green prevented good development of Bacillus coli colonies, ui the fol- 

 lowing experiments with the same amount Bacillus coli grew well. 

 The only points to be ascertained here were whether Bacillus coli and 

 the coconut organism grew equally well, producing colonies of the 

 same form and causing a reduction of the color. The experiments 

 were carried out as follows: 



(1) Agar slant cultures with malachite green. In 24 hours the growth was wet 

 shining and irregular, the same as in ordinary agar tubes. The growth appeared 

 slightly greenish, but this may have been due to the medium. After three days all the 

 tubes showed good growth and all were entirely or nearly bleached. Culture No. 5 

 had entirely reduced the malachite green, but in Bacillus coli a very distinct green was 

 still at the bottom. After four days none of the cultures showed even a trace of the 

 green color. 



(2) Agar plate cultures with malachite green. The malachite green became entirely 

 reduced on all the plates within three days, Bacillus coli accomplishing the reduction 

 more slowly than the others. Plates from cultures No. 5 and Bacillus coli showed only 

 round or nearly round colonies. All the other plates showed a mixture of the round 

 colonies and deeply lobed or radiate-branched ones. As some of the smallest colonies 



• Kiralyfi, G. Ueber den Wert der MalachitKriinnahrboden zur Differenzierung der Tj-phus- und Coli- 

 bacillen. C'entralblalt fiir Bakteriologie, pt. 1, Originale vol. 42, 1900, pp. 276-279, 371-375. 



228 



