Febkuaky 9, 1906.] 



SCIENCE. 



213 



indol reaction; 278 samples in which the 

 determination was carried out quantita- 

 tively showed the following relation be- 

 tween total numbers and occurrence of 

 indol : 



Absorbent Cotton as a Medium for Dis- 

 tributing Pseudomonas radicicola: H. 

 A. Harding and M. J. Prucha, Agricul- 

 tural Experiment Station, Geneva, N. Y. 

 Absorbent cotton Avrapped in paper and 

 tin-foil is now widely used as a means of 

 distributing P. radicicola. 



The large number of failures to get re- 

 sults with this method contrasted with the 

 high percentage of success when the germs 

 ■were shipped in soil, lead to an examina- 

 tion of the packages of inoculated cotton. 



In these examinations the directions on ■ 

 the packages were followed as closely as 

 possible except that sterile solutions were 

 used in order to confine the resulting 

 growth to the germs actually upon the 

 cotton. 



Repeated examinations of twenty-five 

 separate packages of cotton gave only an 

 occasional colony resembling P. radicicola 

 and in most cases not a single suspicious 

 colony was found. 



As a check upon the accuracy of these 

 examinations duplicate samples from six 

 packages were examined in the laboratories 

 of Professor F. D. Chester and Drs. C. E. 

 Marshall, E. M. Houghton and J. G. Lip- 

 man. 



An explanation of the absence of P. 

 radicicola from the inoculated cotton was 

 found in the inability of the germs to with- 

 stand the accompanying desiccation. 



Two separate laboratory trials with 

 bouillon cultures of P. radicicola, placed 

 upon sterile absorbent cotton showed that 

 all but an occasional germ died within a 

 few days. 



Under farm conditions the contamina- 

 tion which enters the fluid usually represses 

 the few surviving P. radicicola. 



The details of the work are given in the 

 New York Agricultural Experiment Sta- 

 tion Bulletin 270. 



The Bacteria of the Root Nodules of the 

 Leguminosece: Karl P. Kellerman and 

 T. D. Beckwith, Bureau of Plant In- 

 dustry, Washington, D. C. 

 For the present preliminary work organ- 

 isms from four species of legumes have 

 been studied : velvet bean, soy bean, garden 

 pea and alfalfa. 



Our laboratory results are summarized 

 briefly as follows: 



Beef agar (made according to formula 

 adopted by the American Public Health 

 .Association) : surface colonies, circular in 

 outline, somewhat convex, rather wet, 

 shining, tinged with straw color, 1 to 6 mm. 

 in diameter. Submerged colonies, lenticu- 

 lar in outline, convex after reaching sur- 

 face, 3.5 by 5 to 0.25 by 0.5 in diameter. 

 Synthetic agar, low in nitrogen (agar 

 flour, 10 g. ; magnesium sulphate, 0.2 g. ; 

 potassium phosphate (monobasic), 1 g. ; 

 cane sugar, 10 g. ; filtered tap water, 1,000 

 c.e.) : surface colonies, circular, translu- 

 cent, convex, wet, shining, 1.5 to 4 mm. in 

 diameter. Submerged colonies, lenticular, 

 convex after reaching surface, 0.5 by 1 to 

 2.5 by 5.5 mm. in diameter.' 



Synthetic agar (same as above plus 4 g. 

 dibasic ammonium phosphate) : surface 

 colonies, circular, somewhat convex, wet, 

 shining, faintly tinged with cream, 1 to 

 5 mm. in diameter. Submerged colonies, 

 lenticular, convex after reaching surface, 

 0.25 by 0.5 to 2.5' b^ '5 mm. in diameter. 



