STEWART'S DISEASE OP SWEET-CORN (MAIZE). 145 



on Fuller's scale and +45 (by addition of malic acid) ; a retarded but prolonged and luxuriant 

 growth in concentrated (4-73, +80) beef-broth; a good growth in 4-30 beef -bouillon ; slow 

 production of acid (lilac color) in litmus milk, followed frequently by the reduction of 

 the litmus; milk cultures alive at end of 7 months; long and copious growth in Uschinsky's 

 solution, yellow rim and pellicle, latter sometimes bearing circular yellow colonies a 

 very good medium for differential purposes ; growth on nutrient starch-jelly greatly stim- 

 ulated by the addition of cane-sugar or galactose; growth stimulated by addition of 10 per 

 cent grape-sugar to +15 nutrient agar; feeble growth in Fermi's solution; strictly aerobic 

 (so far as known) ; cultures on coconut cylinders live some days in an atmosphere of nitro- 

 gen, but make no growth; cultures on white turnip cylinders killed by 15 days' exposure to 

 nitrogen; in atmosphere of carbon dioxide no growth, but organism is not killed on some 

 media, e. g., coconut cylinders. Growth in vacuo depends on amount of air remaining; 

 grape-sugar, cane-sugar, galactose, and mannit are broken up with formation of a small 

 quantity of non-volatile acid; old cultures in Dunham's solution containing rosolic acid 

 and a slight amount of hydrochloric acid become pale red and subsequently geranium-red; 

 Dunham's solution containing indigo-carmine lost its blue color after about 2 weeks; slight 

 amount of indol formed; organism causes a brown stain in the plant (host reaction?) 

 and produces small cavities in parenchyma. Cane-sugar is inverted. Alive on agar in 

 ice-box (i2-i5C.) at end of 14 months and 17 months; lived in litmus milk 7 months and 

 in Uschinsky's solution 4 months. Vigorous and only slightly retarded growth in bouillon 

 over chloroform. Tolerates much sodium chloride. Thermal death-point approximately 

 53 C. ; maximum temperature about 39 C; optimum temperature above 30 C; mini- 

 mum temperature 8 to 9 C. Retains virulence on media for a year, or more, and as 

 long on, or in, infected kernels. Absorbs methylene blue. Group No. 212.2222523. 



NEGATIVE. 



No long chains, filaments, or endospores have been observed ; not stained by Gram's 

 method; no reduction of methylene blue in salted peptone water; no liquefaction of gelatin 

 or Loefner's blood-serum; agar not stained; no gas formed in nitrate agar or any other 

 medium , no filling up of the water in cultures on potato cylinders ; no growth in tomato- 

 fruit juice titrating +68 Fuller's scale (once none in that titrating 4- 60) ; no growth in mul- 

 berry agar (acid) ; no precipitation of the casein or coagulation in milk cultures ; no growth 

 in 80 peptonized beef-bouillon (sodium hydrate); no growth in 30, 35, 40 beef- 

 bouillon; no growth in Cohn's solution; no reduction of nitrates; no clouding of closed end 

 or production of gas in fermentation-tubes ; little or no growth in an atmosphere of hydrogen ; 

 no production of hydrogen sulphide observed in cultures on potato, rutabaga, or yellow 

 globe turnip ; invertase not formed in the absence of sugar ; very little diastase produced ; no 

 trypsin or lab ferments formed; no growth at 40 C, in -f-o beef-bouillon, or in Uschinsky's 

 solution. No growth in peptonized beef-bouillon after long exposure to carbon dioxide. 

 Asparagin not a carbon food. No acid reaction in bouillon containing glycerin or ethyl 

 alcohol; no indol production in 10 days. It was dead at room temperatures after 6 months 

 on potato; 7 months in litmus milk; 8 months in sodium chloride bouillons; 15 months in 

 agar, potato, and beef bouillon, 16 months on peptone beef gelatin. It was dead in the 

 refrigerator on agar after 17.5 months. In carbon dioxide no growth. 



Any organism producing gas, liquefying gelatin, blueing litmus milk or throwing down 

 the casein, reducing nitrates, growing well in Cohn's solution, or refusing to grow in Uschin- 

 sky's solution may be set down at once as something else. 



TREATMENT. 



The proper treatment for this disease remains to be worked out. Four lines of inves- 

 tigation will occur at once to the reader who has followed the text to this point. First and 

 foremost, compulsion applied to the growers of sweet corn for the trade. They must be 



