were present, and a feeble brown stain, thought to have been 

 detected on the fifty-fourth day, was not well enough developed to be 

 recorded as certainly present. On this date there was more than twice 

 as much precipitate as in the corresponding tube of Ps. canipestris. 

 This dextrin had been ten times precipitated with alcohol in the 

 Division of Chemistry, United States Department of Agriculture. It 

 gave a heavy yellowish precipitate on boiling 1 minute in Soxhlet's 

 solution, but no precipitate on boiling 2 minutes in Barfoed's reagent. 



(J:) In distilled water (10 c. c. in tubes of resistant glass) containing 

 ■I per cent of Witte's peptonum siccum and tt per cent of maltose 

 there was no retardation of growth, and for the first week or so the 

 culture closely resembled the preceding. On the twelfth day the fluid 

 was distinctly alkaline to litmus, but it was less cloudy than the pre- 

 ceding and there was far less precipitate. On the twenty-ninth day 

 the fluid was plainly and rather strongh^ alkaline, but there waj only 

 about one-tenth as much precipitate as in the tube containing the 

 dextrin. On the fortieth day the fluid was still cloud3\ but was not 

 browned. The rim was not ver}" abundant and was paler than in the 

 preceding. The precipitate was the same shade of pale yellow as in 

 the tube containing the dextrin, but there was only one-tenth to one= 

 fifteenth as much. On the sixty-fifth da}^ the fluid was strongh^ 

 alkaline, but both in this and in the preceding the bhie color soon 

 disappeared from the neutral litmus paper, leaving it redder than 

 before. No crj^stals were formed. 



In the corresponding tube of Ps. campestris there was a distinct 

 browning of the fluid, which was first noticed on the fortieth day. 

 Ps. jjhaseoli browned neither fluid. 



Crude Vegetable Substances. 



The behavior of Ps. liijacintld in contact with steam sterilized solids 

 and fluids derived from plants has been discussed so fulh^ under 

 Sensitiveness to acids and Growth on solid media that it is onh^ neces- 

 sar}^ here to recapitulate a few of the more important discoveries. 



(1) All ni}' observations tend to show that plant acids, even in 

 comparatively small doses, prevent growth, and that still smaller 

 quantities retard growth. It is, therefore, probable that these acids 

 do not serve directl}^ as food. Certainly the behavior of this organism 

 in nutrient fluids containing malic acid is extremely unlike that of 

 organisms which are believed to use this acid as a food, e. g. Bacillus 

 amylovor^'s. 



(2) Starch, as we have seen, is transformed into substances which 

 can be assimilated only with the greatest diflicult}-. 



(3) Growth on steamed vegetables poor in sugar was always rather 

 meager. Substrata containing rather more sugar gave a correspond- 

 ingl}^ better growth. 



