EXPERIMENT STATION BULLETINS. 



365 



meal were added. In the remaining one, the phosphoric acid and the 

 nitrogen of the bone were replaced by their respective equivalents in 

 superphosphate of lime and sodium nitrate. In addition to the bone, 

 21/0 grams of glucose were added to some pots and the same amount of 

 xylose to others wliile still other pots contained no sugar, the object be- 

 ing to determine whether the carbon dioxide resulting from the fer- 

 mentation of these carbohydrates would exert i\n increased solvent act- 

 ion over the pots which contained no sugar. The pots were inoculated 

 with 100 c. c. suspension of the different organisms employed six days 

 before planting the oats. At the end of the growing period, the crop 

 was harvested and separate weighings made of the grain and straw from 

 each pot. Each series in the experiment contained ten pots and the 

 r(^sults given are based upon the average of these ten. The results fol- 

 low : 



Table No. 2. Stoklasa's Pot Experiments. 



Treatment of Pots. 



Grain. 



Straw. 

 g. 



Not inoculated. Bone meal 



Not inoculated. Superphosphate and Chili saltpeter 



B. megaterium. Bone meal without glucose 



B. megaterium. Bone meal and glucose 



B. megaterium. Bone meal and xylose 



B. mesentericus vulgatus. Bone meal and glucose . . 



B. mycoides. Bone meal and glucose 



B. butyricus. Bone meal and glucose 



B. fluorescens liquefaciens. Bone meal and glucose . . 



161.32 

 213.98 

 246.79 

 285.88 

 320 . 52 

 283.21 

 235.26 

 230.79 

 165.26 



213.81 

 260.13 

 267.85 

 306.11 

 398 . 04 

 353.77 

 289.03 

 285.99 

 272.26 



By referring to Table No. 2, it will be seen: — 



First, that in every case where the pots containing bone were inocu- 

 lated there has been an increase in the crop over the uninoculated pots. 



Second, the j)Ots inoculated with B. megaterium to which glucose 

 and xylose were added show an increase over the inoculated pot with- 

 out sugar. 



Third, all inoculated pots containing a carbohydrate, with the ex- 

 ception of the B. fluorescens liquefaciens series, gave a heavier yield 

 than the B. megaterium pots with no carbohydrates. It seems unfortu- 

 nate that control pots without the sugar were not prepared for each 

 organism. Stoklnsa attributes the greater weight of oats in the pots 

 containing glucose and xylose to the carbon dioxide coming from the 

 fermentation of these carbohydrates, acting upon the insoluble com- 

 pounds of the bone and liberating phosphoric acid and nitrogen. This 

 is undoubtedh' an important factor in explaining the increased fertil- 

 ity providing all of the organisms experimented with are capable of 

 l)roducing carbon dioxide from the carboyhydrates named, but it is prob- 

 ably not the only one to be considered, since in the presence of such 

 quantities of organic matter as occur in tlie average field soil, we should 

 expect to find abundant material which would give rise to dilute or- 

 ganic acids when acted upon by soil bacteria. These acids, tho weak, 

 nevertheless cannot be disregarded in a question of solubility. 



Koch and Krober (1) in their recent work have shown that a number 

 of insoluble phosphates are rendered soluble by the acids formed by 

 sewage and soil bacteria from dextrose. They have employed the same 



