40 



(solidifiofl). Oil the eighteenth day the whole sabstratuni was browned 

 and this color was a much deeper l)rown than in the corresponding 

 tul)e of J's. hyaclntlii. On the fiftieth day the color was l)urnt umlier, 

 and on the sixty-fourth day dark burnt uuiber. The slime was neu- 

 tral or slighth' alkaline on the thirtj'-fourth day, and feebly alkaline 

 on the sixt3'-fourth da}". The tissues were softened. 



On this substratum Ps. stewarti made a thin buff yellow, slightly 

 iridescent growth. On the seventh day there Avas one-fifth as much 

 growth as in corresponding tubes of P>i. hyaeintJu and one-tenth as 

 much as in Ps. camjjestrls. Growth did not increase much after the 

 first or second week, and there was no browning or softening of the 

 substratum. The culture was alkaline on the thirty-fourth and sixty- 

 fourth daj's. After a time the water surrounding the turnip contained a 

 moderate amount of buft" yellow precipitate, but it never became thick 

 or solid from excessive multiplication of the bacteria. 



Rutabaga. 



Test-tube cultures of this turnip (which had smooth glaucous leaves) 

 were prepared with distilled water in the ordinary way (see Potato). 

 The tests were made at the same time and in the same manner as on 

 the 3"ellow globe turnip, and the results were much the same. 



With ^s-. hyacintJil the growth was copious from the start, and not 

 onh' covered the cylinder, but filled the fluid (solid). There was no 

 stain of the substratum until after the twentj^-seventh da}', but this 

 was covered by the bacterial growth so as not to be exposed any- 

 where directly to the air. On the fiftieth da}^ the bacterial slime exhib- 

 ited a smooth, wet, dirty, brownish yellow surface. The upper part 

 of the sul)stratum was now browned. The slime was acid to neutral 

 litmus, leaving a distinct reddish color as it dried, ajid the cylinder was 

 softened so that it mashed easih" with a glass rod. The fluid was still 

 plainl}' acid after adding 25 c. c. of water and stirring. On boiling 

 only a trace of acid was given off in the steam. On continuing the 

 boiling so that the fluid was reduced to 6 c. c. it was more strongly 

 acid, and the acidit}' became still more pronounced on reducing it to 3 

 c. c. The boiled fluid had a slighth' bitter taste. There was a slow 

 evolution of gas and no white precipitate when this rather thick slime 

 was put into barium chloride water (acid). 



On this substratum Ps. campestrtx grew ver}' promptly. By the 

 seventh day the fluid was grown solid and the cylinder in the air bore 

 on all parts a very copious, wet, shining, smooth, yellow growth. At 

 this time there was alread}- a slight stain of the substratum. This 

 stain became more pronounced and extended to the whole substratum 

 on or before the eighteenth day. This color (slime and substratum) 

 gradualh' deepened through raw umber (fiftieth da}-) to mummy brown 

 (sixty-fourth day). On the thirty-fourth and sixty-fourth days the 



