90 



HISTORY AND CAUSE OF THE COCONUT BUD-EOT. 



Table XVIII. — Growth of cultures Nos. 1 to 6 and Bacillus coli on plates of Endo's 

 viedium (Ruata's formula), April 26 to May 6, 1910, at S7° C. 



Culture. 



2 days. 



Coconut 1 . . Numerous white colo- 

 nies. 



Coconut 2 . . Numerous round white 

 colonies. 



Coconut 3 do 



Coconut 4..; do. 



Coconut 5.. do. 



Coconut G.. do. 



B. coli i Numerous round white 



and some pink colo- 

 nies. 



4 days. 



Numerous white colo- 

 nies. 



About one-fifth of colo- 

 nies are pink. 



Numerous roimd white 

 colonies. 



Some of colonies are 



iridescent. 

 Colonies same form; aU 



bright pink in color. 

 Some of colonies are 



iridescent and some 



pink. 

 Colonies all same form; 



all bright pink in 



color. 



6 days. 



Numerous white colo- 

 nies. 

 Same as before 



Many pink colonies 

 about circum ference ; 

 center white. 



Same as before , 



do 



About one-eighth of 

 the plate is pink. 



About one-fifth of the 

 colonies are bright 

 pink. 



10 days. 



No color. 



Only a trace ol 

 pink. 

 Do. 



Do. 

 Do. 

 Do. 



Bright red all over. 



Slant-tube cultures on Endows medium, May 4 to 11, 1910, at 37° C. 



Two days: Bacillus coli and Bacillus colia. were bright pink. Some of the others 

 showed a tinge of color but nothing more, although the growth was good. 



Three days: Nos. 1 and 1 a are slightly pink. Bacillus coli and Bacillus colia, are 

 bright red throughout the medium. AU others show a bright pink surface 

 growth, but the bottom of these tubes is colorless. 



Five days: Nos. 1 and 1 a are slightly pink. All the others are bright red through- 

 out. Bacillus coli and iJaeiWtts coZt a are a trifle brighter than the others. The 

 growth is good in all cases; pink, smooth, and wet shining. 



Seven days: No change. All but 1 and 1 a still retain their bright color. 



From these experiments it may be seen that the reaction of the 

 medium seems to be the same for the coconut cultures as for BaciUus 

 coli. Luxuriant white colonies which appear in transmitted light 

 like drops of water first develop on the medium. Then appears a 

 sUght pink color, as seen in direct light, or an iridescence passing 

 from pink to green and blue, as seen in reflected hght. Later the 

 pink darkens to a deep red and the colonies appear opaque. There is 

 no sign of the greenish metallic fluorescence characteristic of fuchsin 

 and mentioned by Ruata as a part of the typical reaction with 

 BaciUus coli. In an attempt to obtain this reaction on old cultures 

 two plates were placed at 47° C. until they were completely dried 

 down. The bright red deepened to a dark magenta, but in no case 

 were there any signs of the fuchsin metalhc luster. 



In the original make-up of the medium the fuchsin is decolorized 

 by the sodium sulphite. This action probably results in the forma- 

 tion of sodium sulphate and some colorless derivative of fuchsin. 

 As a result of the growth of the organism some reducing agent is 

 formed which removes the atom of oxygen from the sulphate and 

 restores it to the fuchsin, thus yielding sodium sulphite and fuchsin 

 if good growth takes place. 



228 



