LABORATORY AND GREENHOUSE STUDIES. 117 



November, 1910, Miss Lucia McCulloch made the following addi- 

 tional tests: A medium containing 1 per cent peptone, 1 per cent dex- 

 trose, and 0. 1 per cent succinic acid was inoculated from slant-agar cul- 

 kires 3 days old of the six coconut strains and four Bacillus coli strains. 

 Another medium containing 1 per cent peptone, 1 per cent dextrose, 

 and 0.05 per cent succinic acid was inoculated from the same agar 

 cultures. One 1 -millimeter loop was used for inoculation and the 

 tubes were incubated at 33° C. At the end of 48 hours a very 

 moderate growth appeared in all the cultures, represented by thin 

 clouding, floccident particles, and precipitate; no pellicles. Seem- 

 ingly there is no particular difference in growth in the two media. 

 After 10 days the medium containing 0.05 per cent succinic acid 

 was moderately cloudy, while that containing 0.1 per cent succinic 

 acid was much clearer. The amount and character of the pre- 

 cipitate in the two media are very similar. 



After 18 days the 0.05 per cent succinic acid was still cloudy 

 while the 0.1 per cent succinic acid was practically clear. There 

 seemed to be slightly more precipitate in the weaker acid medium. 



COCONUT CYLINDERS. 



Small pieces of firm coconut tissue from the petioles of leaves 

 were placed in test tubes and a solution of 1 per cent dextrose was 

 added in amounts to cover the lower half of the cylinder. The 

 sugar was for the purpose of facilitating the growth of the organism, 

 the tissues used being too hard to furnish much nutriment. 



After 1 day at 37° C: Growth in each tube indicated by clouding of the liquid. 

 After 2 days: The liquid and pieces of coconut much discolored. Slow growth 



on some pieces, blackening and reddening of others. 

 After 10 days: Check, liquid clear; cylinder hard. 



Bacillus coli a, cylinders blackened — not softened, nor slimy. 



B. coli, one cylinder soft, but not disintegrated; microscopic examination of 



section shows no change. 

 No. 4, brown, slimy growth on a portion of the cut surface of the cylinder which 



is reddish black; portion of the side blackened; by squeezing the cylinder 



drops of reddish thick liquid are forced out; no soft rot; the cylinder remains 



firm. 

 No. 6, blackening of the tissues as in others; also a rotting of the soft tissues. 

 No. 2, abundant orange-yellow precipitate and same brown slime as in No. 4; 



tissue woody, not soft rotted. 

 No. 3, same abundant orange-yellow precipitate as in Nos. 2 and 4; cylinder 



blackened but not soft rotted. 

 No. 5, same as Nos. 2, 3, and 4. 

 No. 5 a, same orange-yellow precipitate and same brown slime on cut surface 



of blackened cylinder. 

 No. 1, same abundant orange-yellow precipitate as in others. 



This experiment was repeated under the same conditions, but 

 there was only a flocculent clouding which quickly cleared away. 



228 



