ZOOLOCV AND BOTANY, MICROSCOPY, ETC. 689 



Bacterial Disease of the Potato.* — G. Delacroix describes a bac- 

 terial disease affecting the potato iu western and central France. The 

 same disease, according to Johnson, is prevalent iu Ireland. All soils 

 are liable, but especially those which possess little lime. The bac- 

 terium is identified as Bacillus Solanacearum E. F. Smith. It appears 

 to gain entrance through wounds made by insects, &c, on the sub- 

 terranean parts of the stem. From the wound entrance the microbes 

 spread upwards and downwards, chiefly through the vessels. The 

 destruction of the plants is hastened by the attacks of numerous other 

 parasitic fungi. 



Bacillus putrefaciens sp. n., a new Parasite on Plants, f — After a 

 general account of the action of fungus parasites on plants, both ex- 

 ternal and internal, M. J. Ray describes, under this name, a new bacterial 

 parasite which attacks wheat, oat, lupin, haricot, sunflower, radish, and 

 mustard. Cultivated on potato, carrot, bouillon of haricot or lupin, it 

 forms a thick grey mucus, tending towards rose-colour ; on bouillon it 

 forms a large quantity of diastase. It is very destructive to vegetable 

 tissues. 



Spore-formation of Anthrax under Anaerobic Conditions. — Dr. 

 A. Klett's X experiments were made with the object of ascertaining 

 the effect of atmospheres of nitrogen and hydrogen, and his results 

 showed that spore-formation was independent of the presence of 

 oxygen. Spores were formed freely in the nitrogen atmosphere, sparely 

 in that of hydrogen. Hence oxygen is not a necessity, but every gas 

 exerts a specific influence. 



Dr. E. Jacobitz § finds, in opposition to Klett, that when anthrax is 

 cultivated in an atmosphere of nitrogen spores are not formed, at any 

 rate when agar is used as the nutrient medium. 



Denitrification. — According to O. Lemmermann,|| the functions of 

 the denitrifying bacteria, of which 23 varieties are known, are con- 

 trolled by the absence or presence of suitable carbonaceous matter and 

 oxygen when the conditions are in other respects normal. The results 

 of experiments indicate that in practice denitrification has not the im- 

 portance which has been ascribed to it. 



G. Ampola and C. Ulpiani 1[ describe experiments showing that if 

 the soil fulfils the conditions necessary for denitrification, that is, if it 

 contains bacteria, nitrate, and assimilable organic material, the nitrate is 

 completely reduced to free nitrogen. Hence stable manure and sodium 

 nitrate should not be applied simultaneously, but the former should be 

 allowed to reach its full maturity on the soil before the latter is added. 

 They also found that calcium nitrate was a better manure than sodium 

 nitrate ; that it offers far greater resistance to denitrifying micro- 

 organisms than the sodium salt ; and that the question of denitrification 



* Comptes Keudus, exxxiii. (1901) pp. 417-9. 

 t Rev. Gen. de Bot. (Bonnier), xiii. (1901) pp. 145-51. 

 % Zeiischr. f. Hygiene, xxxv. (1900) pp. 420-38. 

 § Centralbl. Bakt., l te Abt., xxx. (1901) pp. 232-9. 

 || Bied. Centr., xxx. (1901) pp. 368-9. 



f Gazzetta, xxxi. (1901) i. pp. 185-221. See Journ. Chem. Soc., lxxx. (1901) 

 Abstr. ii. p. 524. 



