168 ROYAL SOCIETY OF CANADA 



On streak cultures, on inclined ash-maltose-agar, in two or three 

 days there is a moist, shining, transparent growth along the line of 

 inoculation. As this growth increases, it is transparent at the edges, 

 becoming gradually translucent, then white and opaque towards the 

 middle. It is at first watery, then mucilaginous, and it flows down 

 the inclined surface of the agar by its own weight, and accumulates 

 as a white, slimy growth at the bottom. It spreads laterally and 

 forms a broad band or may cover the whole surface of the agar. At 

 room temperature growth is a little slower, but otherwise as at 25° C. 



Groivlh in asli-maltose-ivaier media. — In January, 1905, a series 

 of liquid media were inoculated with pure cultures isolated from nodules 

 of red clover, alfalfa, vetch, bean and soy bean. The inoculated media 

 were kept at 25° C. and observed daily, and the following conclusions 

 were drawn: Some growth takes place in distilled water with 1 per 

 cent of maltose, but such a medium is not favourable. The liquid 

 becomes turbid, sediment forms which is not ropy but which diffuses 

 on shaking, and a thin, wide ring of growth forms on the glass down- 

 wards from the surface. Media made in the manner already described, 

 with distilled water, 100 parts; maltose, 1 part; and ashes, |, 1 and 1^ 

 parrs respectively, and varying from neutral to alkaline — 3°, are 

 parts respectively, and varying from neutral to alkaline — 3°, are fav- 

 ourable. Growth begins usually in three or four days and increases 

 visibly for fifteen days. The liquid becomes turbid and the turbidity 

 continues and increases to a thick white layer. On shaking with a 

 circular motion, this growth rises in the liquid and twists or coils on 

 itself. It is not easily diffused by shaking, and again settles do\\Ti 

 when left standing. There may be strings of slimy growth suspended 

 on the body of the liquid. A ring of growth appears on the glass in 

 usually nine or ten days just beneath the surface of the liquid and 

 gradually increases to a thick, slimy ring which may break in pieces 

 and fall to the bottom and again form at the surface. A partial film 

 may form. 



Media made with distilled water, 100 parts; maltose, 1 part; and 

 ashes, 2 parts and 2-^ parts, respectively, are less favourable. The body 

 of the liquid remains clear and a slimy white growth takes place at 

 the bottom in fifteen days or more. 



In larger flask cultures, a ring forms and an especially copious 

 growth spreads over the surface. From the lower side of this mucila- 

 ginous film many delicate slimy filaments hang down some of which 

 reach and unite with the copious slimy sediment. 



7. Morphology of Ps. radicicola. The cells from colonies are min- 

 ute or small rods, single or in twos, often swollen at one end or near the- 



