1014 EXPERIMENT STATION RECORD. 



FERMENTATION— BACTERIOLOGY. 



Potato as a culture medium, with some notes on a synthesized 

 substitute, E. F. Smith (Proc. Amer. Assoc. Adv. Sci., 47 (1898), pp. 

 411. 412). — After discussing some of the advantages and disadvantages 

 of potato as a substratum for the growth of fungi and bacteria, the 

 author states that he considers it a very useful substance which should 

 not be discarded. He further describes a synthesized medium which 

 he has found free from many of the objections urged against the potato, 

 while possessing most of its good qualities. It consists of potato starch 

 combined with a modified Uschinsky solution. The methods for prepa- 

 ration of this medium, which the author has designated as "nutrient 

 starch jelly," are fully given. It is stated that many orgauisms which 

 previously made only very feeble growth, in this medium grow exceed- 

 ingly well. This medium possesses excellent keeping qualities and is 

 well adapted to the long-continued growth of many organisms, both 

 fungi and bacteria, and is said to be particularly valuable for studying 

 the diastatic action of various bacteria, some of which grow luxuriantly 

 and convert starch into sugar very rapidly, while others make very feeble 

 growth, being able to convert starch with the greatest difficulty. 



Which forms of carbohydrates are required by denitrifying 

 organisms for their vital processes? J. Stoklasa (Ztschr. Landw. 

 Versuchw. Oesterr., 1898, p. 371; abs. in Cliem. Ztg., 22 (1898), Xo. 99, 

 Bepert., p. 315). — The author's experiments indicate that xylan, which 

 with other furfuroids occurs abundantly iu straw and manure, when 

 hydrolyzed to xylose furnishes the most natural and favorable carbo- 

 hydrate food for denitrifying organisms. Arabinose is not so well suited 

 to these organisms as xylose. The author made experiments with differ- 

 ent carbohydrates in vegetation pots inoculated with Bacillus denitrifi- 

 cans. On all pots receiving glucose the yield of oats was normal, while on 

 those receiving xylose the yield was almost a fourth less than in case of 

 pots which had received nitrate of soda and superphosphate. The 

 results on the pots to which arabinose had been applied were prac- 

 tically the same as with those receiving glucose. 



Very different results were obtained in experiments with organisms 

 which produce ammonia in the soil. Soils which were inoculated with 

 Bacillus megatherium and B. mycoides in the presence of nitrates and 

 xylose gave a higher yield of oats than those which had not been so 

 inoculated. The author suggests that this was due to the reduction of 

 the nitrate to ammonia and the thereby increased capacity of the soil 

 for fixing the free nitrogen of the air. The fact that soils rich in 

 furfuroids, especially xylan, contain only traces of nitrates is believed 

 by the author to be due to biochemical action in the soil which quickly 

 reduces the nitrates to ammonia. There is a large number of orgauisms 

 which reduce nitrates and nitrites to ammonia. 



A report on bacteriological investigations of the fermentation 

 of tobacco, J. H.Verhout (Teysmannia, 9 (1898), IVo. 2-3, pp. 118-144; 

 abs. in Centbl, BaU. u. Par., 2. AM., 4 (1898), No. 20, pp. 778, 779).— 

 The author gives a preliminary report on his investigations of the 



