38 



radish. At this time the color was approximately burnt umber (R. 

 1II-8), but it was a trifle lighter than that color and appeared to have 

 a trace of red in it. 



The stain in old cultures was always a distinct but feeble brown 

 and differed from the stain of P><. campestris principally in being a 

 shade or two lighter. 



Yellow Turnip. 



This medium was made in the same way as the preceding. The 

 turnips were of the same habit of growth as the white ones but were 

 sweeter to the taste and were distinctly yellow. The relative amount 

 of sugar in the two kinds was not determined. 



Ps. hyacinthi grew remarkably well on this substratum and without 

 any marked retardation. At room temperatures of IS"' to 25^ C. the 

 bacterial layer was usually visible on the third day. A week after 

 inoculation growth in the air was "copious" to "very copious," and 

 growth in the water had been sufficient to produce a sirup}^ liquid. 

 This growth continued for several weeks, entirely hiding the aerial 

 part of the cylinder and converting all of the fluid (1 to 2 c. c.) into a 

 solid slime which would not flow. In one tube, at the end of 8 days, 

 there was 100 times as much growth as in corresponding cultures on 

 potato. In other words, the organism behaved on this substratum 

 exactly after the manner of Ps. canqMstris and Ps. 2yhmeoU on potato. 



At room temperatures the growth was smooth, wet-shining, and 

 homogeneous-looking from the start, and it remained so for 2 months. 

 There was never any shagreen surface or other surface indication of 

 zoogloeifi; nor was the dense copious slime stick}^ (eighth day). 



The color of the slime was pale yellow; i. e., distincth^ paler than 

 on some other media. Examinations of 4 difi'erent cultures on the 

 third, fifth, seventh, eighth, twelfth, twentieth, twenty-second, and 

 thirty -second days all agree in this particular. On the fifth day the 

 slime was a little brighter than Naples yellow. On the eighth day the 

 color of the slime from another tube closely resembled Naples vellow, 

 but was lighter j^ellow than the slime from a corresponding culture on 

 carrot. In one instance the precipitate was canary yellow, while the 

 aerial slime was paler yellow. On the fifty-fourth day, viewed without 

 removal from the tube, the slime appeared to be russet color, but on 

 putting a mass of it on white paper and comparing with Ridgway's 

 plates its color was ochraceous. 



On the eighth day the slime was distinctly alkaline to neutral litmus 

 paper (one tube only was tested). In another tube, on the fiftj^-sixth 

 day, the slime was feebly alkaline. 



No stain of the fluid or of the substratum was visible during the first 

 week of growth, but during the second or third week a brown color 

 appeared and slowly increased in depth. On the twentj^-second day 



