[nAUKisoN A barlow] XODULE ORGAXISxM OF THE LEGUMINOSAE 1S9 



Our medium record shows (see tabulated summary of media) that 

 during the past two j-^ars we have made up some twenty-five lots of 

 ash-maltose-ag-ar, var}dng in amount from a few hundred cubic centi- 

 metres to 8,000 c.c. in a single lot. The larger lots were used for 

 preparing nitro-cultures for distribution, "W'e have also made seven 

 lots of ash agar with sucrose or with sucrose or maltose and acid potas- 

 sium phosphate. 



Some twenty lots of liquid media have been prepared as follows : — 

 Ash maltose water, 15 lots; ash sucrose water, 2 lots; ash water with 

 sucrose or maltose and acid potassium phosphate, -^ to 2 parts per 100, 

 5 lots. 



Pseudomonas radicicola from ten different species of Leguminosae 

 have been inoculated and grown in most of these media, and notes 

 have been kept of the cultures. Most of the cultures were isolated 

 in the spring and summer of 1904 and have been kept in stock since 

 that date. 



Sugar-asli-waier for Ps. radicicola. — By referring to the tables of 

 media, it will be seen that the materials and proportions have been 

 varied. ^laltose was found to be more favourable than dertrose or 

 sucrose. Ashes from maple wood, from mixed beech and maple wood, 

 from elm and from tamarack were found equally favourable. The 

 ashes were obtained fresh and passed through a fine sieve — and some- 

 times reburned to consume remaining particles of carbon — and were 

 then stored in glass jars until used. The distilled water was con- 

 densed on tin and stored in glass. Water from artesian wells wa.s also 

 used and was found equally favourable. 



Methods of preparation. — The bacteria were found to grow as well, 

 or better, in a filtrate from ashes as when the whole of the insoluble 

 residue was retained and so a filtrate was generally used. For 1,000 

 parts of cold water take 2.5 to 25 parts by weight of wood ashes, shake 

 together and filter at once or after half an hour; or heat together 

 to boiling, boil a minute and filter. The filtrate should be almost 

 colourless and more alkaline as the amount of ash and as the time 

 before filtration is increased. To 1,000 parts of the filtrate add 5 to 

 20 parts of maltose, sucrose or dextrose, maltose being best; heat in 

 flowing steam and boil a moment over the flame or heat in the auto- 

 clave for 20 minutes or more at 10 pounds steam pressure. The 

 medium will var\' from faintly alkaline to phenolphthlein to alkaline 

 —6°, according to the amount of ash used. The colour will vary 

 fiom a yellowish tint to a deep amber, being darker as more ash is 

 used and as the amount of heating is increased. If desired, acid 

 potassium phosphate, 2 to 5 parts per 1,000, may be added at any 



