70 



HISTORY AND CAUSE OF THE COCONUT BUD-EOT. 



organism has been retained tlu'ougiiout, and lliat tliere has been no 

 discernible contamination of tlie tubes. 



PRODUCTION OF ACID AND GAS IN LACTOSE. 



Titration of cultures in lactose fermentation tubes showed coconut 

 No. 4 to be + 15 and No. 6 +15 on Fuller's scale after growth for 15 

 days. No checks were titrated at this time, but they usually ran 

 about +5. 



In fermentation tubes containing 1 per cent peptone plus 1 per cent 

 lactose in 24 hours no gas was shown. After five days at 22° C. the 

 showmg was as follows: Tube 1 a, 34 mm.; tube 2 a, 20; tube 3, 

 26; tube 4, 20; tube 5 a, 27; tube 6 a, 24. 



After 15 days No. 5 a had produced 28 mm. of gas. In 21 days No. 

 6 a showed only 22 mm. of gas. Evidently the gas production had 

 ceased and that already formed was being partly absorbed. 



Table VIII shows the results of a similar experiment in peptone 

 plus lactose at 22° C. : 



Table VIII. — Amount of gas (in mm.) produced by various cultures in experiment with 

 1 per cent peptone plus 1 per cent lactose, at 22° C, February 4 to 18, 1910. 



In the lactose as in the dextrose the ability of the organism to pro- 

 duce gas appears to vary. In the first experiment all of the cultures 

 formed gas; and in the later experiment only three of them, and they 

 apparently with difficulty. The fact that the organism can effect this 

 change, even though it does not always do so, is of value in deter- 

 mining its characteristics. No experiments were carried out usmg 

 beef bouillon with lactose. In general, the acid production m lactose 

 seems to be less than in dextrose; and the gas formation also, at least 

 in a peptone medium, seems to be effected with greater difficulty 

 than in dextrose. 



PRODUCTION OF ACID AND GAS IN SACCHAROSE. 



Cultures in peptone plus cane sugar titrated after five days at 22° C, 

 coconut No. 1, +14; No. 5, +13. No check was titrated at this 

 time, but they usually were about +5. The following table shows 

 the gas production: 



228 



