BULLETIN 231] WALNUT CULTURE IN CALIFORNIA. 349 



Dunham Solution. The growth in this medium shows very much the 

 same characteristics as in bouillon. In cultures over a week old the 

 liquid is clouded. 



Carbohydrates in Bouillon. The walnut organism was grown in the 

 following bouillons, containing, respectively, 2 per cent glucose, dex- 

 trose, lactose and glycerine saccharose. These solutions were made up 

 by adding the carbohydrate to a solution of meat peptone, solution made 

 after the formula: 1 per cent Witte's peptone, 0.5 per cent sodium 

 chloride, 0.5 per cent Liebig's meat extract. These solutions titrated 

 plus 12 Fuller's scale. Growth took place within forty-eight hours, 

 and at the end of five days fine growth showed in all the tubes of 

 this series. The glucose series of tubes showed a well developed ring 

 formation, while in the other media there were traces of ring formation, 

 but much less than in glucose. There was no complete pellicle observed 

 in these tubes. They were titrated, but showed no increase of acid. 



Cohn Solution. Formula as given by E. F. Smith was used.* Five 

 tubes were inoculated with forty-eight-hour culture of walnut organism, 

 but after three months there was no growth in tubes. 



Milk. The cream was removed from milk that had set over night in 

 an ice box. The same was filtered and sterilized in steam sterilizer. 

 Reaction was plus 10 to 15 Fuller's scale. These tubes were inoculated 

 and grown at temperatures 25 to 27 C. In three days the separation 

 of the casein was first observed. The coagulum is formed rather slowly 

 and even after five days there is little separation of the whey, and no 

 pellicle to be seen at this time. The curd and whey gradually separate 

 from each other, the former becoming solid. The casein is soon acted 

 upon by another enzyme and is gradually redissolved, probably by a 

 trypsin ferment. This process of digestion takes place usually rather 

 slowly, several months often being required for completion. After a 

 month the white curd may be observed at the bottom of the tube 

 while the liquid above is of a yellowish color (yellowish straw color ).t 

 At first the whey is clear and nearly colorless, but changes to a yellowish 

 color, as stated above, when reabsorption of the casein has taken place. 

 Upon a microscopic examination of the liquid directly above the casein 

 that is in process of reabsorption many crystals can be seen. The most 

 conspicuous of these are long, needle-like crystals. A pellicle at length 

 forms on the surface of the liquid in the milk tubes. 



Litmus Milk. The characteristics are very much like those just given 

 for milk. Separation of casein takes place by a rennet ferment, or 

 rarely digestion occurs without casein separation ; the tubes under these 



* Bacteria in Relation to Plant Diseases. 

 tRepertoire de Couleurs, Henri Dauthenay. 



