94 HISTORY AND CAUSE OF THE COCONUT BUD-EOT. 



amount present. The only conclusion is that there was some impu- 

 rity in the chemical used. It is probable that ammonia would be 

 produced only in the presence of some product as peptone or such as 

 might be in beef bouillon. In a solution containing merely peptone 

 plus NaCl (Dunham's solution) check tube titrated +9, and cultures 

 grown 11 days were only +5, indicating a slight alkali production. 



ENZYMES IN MILK. 



In the coagulation of milk by the coconu-e organism the question 

 arises whether the reaction was due to the acid formed or to an enzyme 

 produced. This question has been discussed by O'Hehir ^ and by 

 Savage,2 both of whom claim that there may be a small degree of 

 enzymatic action as well as acid coagulation. 



Cultures of both the coconut organism and Bacillus coli were made 

 in sterile Htmus milk tubes. After incubation for nine days, when a 

 good coagulation had taken place in all the tubes, ammonia was added 

 to the tubes in quantity more than sufficient to neutralize the acid in 

 the cultures. Practically complete dissolution of the curd quickly 

 took place. The only residue left might be attributed to the small 

 amount of fat in the tubes, as it had not been completely removed 

 in the preparation of the medium. This experiment would indicate 

 the coagulation to be entirely an acid one. 



Attempts were made to free milk completely from its fat by repeated 

 boiling and subsequent skimming off of the film formed on the surface, 

 but without success. 



Dr. Erwin F. Smith suggested the addition of calcium carbonate 

 to the milk to take up the acid formed by the growth of the organism. 

 AccorcUngly, cultures were made in Htmus milk and in plain sterile 

 milk, both containing 1 per cent CaCOg. Coagulation took place, and 

 the tubes were subsequently treated with ammonia. Their behavior 

 and appearance are shown in Tables XIX and XX. 



1 O'Hehir, C. Jocelyn. A Note on the Coagulation of MiLk by Bacillus Coli Communis. Journal of 

 Pathology and Bacteriology, vol. 11, 1906-7, pp. 405-407. 



« Savage, W. G. The Coagulation of Milk by Bacillus Coli Communis. Journal of Pathology and Bac- 

 teriology, vol. 10, 1904-5, pp. 90-97. 

 228 



