154 Journal of Agricultural Research voi. xix,no.4 



power is moderate; gelatin is liquefied slowly, beginning in 2 days and not complete 

 in 60 days; reduction of litmus occurs in milk, and the casein is digested without 

 curdling; milk curdles in 5 days, and peptonization is completed in 5 weeks. No acid 

 is produced in milk. Oxidations of proteins are incomplete; ammonia is produced; 

 hydrogen sulphid, gas, and indol are not produced. Nitrates are not reduced. There 

 is slight diastasic action on potato cylinders. Good growth in Uschinsky's solution 

 and in Fermi's solution. Growth in Cohn's solution is scanty. Maximum tempera- 

 ture for growth is 31° C, minimum below 0°, optimum 24° to 25°, thermal death point 

 between 47° and 48°. Tolerates sodium hydroxid to —18 Fuller's scale and hydro- 

 chloric acid to +27. The optimum reaction for groWth is +5 Fuller's scale. Gram- 

 negative, not acid-fast, stains readily and uniformly with gentian violet and methy- 

 lene blue. Stains more or less irregularly with carbol fuchsin (often polar staining). 

 Sensitive to drying; 87 per cent killed by freezing, 80 per cent killed by sunlight. 

 Vitality on culture media long. Pathogenic on varieties of cultivated oats and to a 

 slight degree on wheat, rye, and barley, producing oval halolike lesions of chlorotic 

 tissue surrounding dead brown centers of infection. 



Beef-peptone agar and beef bouillon are favorable media for prolonged growth. 

 Growth on potato agar brings out more distinguishing characteristics. 



II. — ISOI^ATION NO. 36 



This isolation was made from a halo lesion on oats obtained from 

 "Wooster, Ohio, in June, 1917. It has the same group number as the 

 stock halo organism just described but differs from it in the characters 

 mentioned below. The differences, though not very marked, seem to be 

 fairly constant, while the lesions from which the cultures were isolated 

 and which they produce in inoculation work can not be distinguished. 

 The stock organism seems to be slightly more virulent. 



Morphology. — The organism occurs singly or in twos but seldom in 

 long chains (Pi. 34, A). Stained by Ribbert's capsule stain it measures 

 from I.I to 3 /i in length and from 0.5 to 0.8 /i, in width, not including the 

 capsule, with an average measurement of 0.66 by 2.1 /x. 



Beef agar plates. — On + lo beef-peptone agar, the surface colonies 

 remain round, and the margin tends to remain entire (Pi. 31, D). 



PoTATo-DEXTROsE AGAR STROKE. — ^Two-day-old slants from broth 

 show moderate flatter growth, which is filiform and dull, with more or 

 less wrinkling on the surface. The growth is somewhat translucent and 

 of a butyrous to slightly membranous consistency (Pi. 30, B, a). 



Gelatin stab. — Liquefaction is more rapid, being complete in 40 days. 



Toleration of sodium chlorid. — Same as stock, but slides from a 

 2 per cent solution stained with carbol fuchsin show only a few scattered 

 short chains. 



Litmus milk. — Litmus is not reduced. 



Methylene blue. — Digestion of casein a little slower than with stock. 



Uschinsky's solution. — No chains on slide stained with carbol 

 fuchsin. 



Cohn's solution. — Clouding heavier than with stock. Crystals are 

 formed on the sides of the tubes. 



Starch agar. — The organism showed a feeble diastasic action on 

 Starch. 



