12; 5 



poor soil by a(l(lini> lo Dial soil lai'gc amouiils of dihy- 

 (Iroxystoaric acid. In orik-i* lo Usl this, a luinihrr (>{' 

 pots were treated as shown in the table ])elow. and iwo 

 crops iijrown, as in the case of the other experiments 

 reported. Tlie natural soil on which this test was made 

 is infertile, apparently, because of a great deficiency of 

 nitrogen, since neither phosphorus, nor potassium, nor 

 lime, nor combinations of these increased the yields 

 materially, while a complete fertilizer resulted in a 

 most vigorous growth of plants, showing that it was the 

 deficiency of nitrogen that caused the poor growth. 

 Now, when dihydroxystearic acid is used alone or in 

 combination with ferfilizeis and lime, the effect of the 

 supposedly toxic compound is almost nil, as may readi- 

 ly be seen by a comparison of the yields reported in: 

 Table VIII. At no time during the progress of the work 

 was there an apparent injury from this material al- 

 though it has been shown to be decidedly toxic to' 

 plants, in solution cultures. A crop of corn followed 

 after the oats, and growths obtained showed no indica- 

 tion of injury by dihydroxystearic acid. The corn 

 received no second dose of the special treatment, but 

 the fertilizer treatment given to the oats was repeated' 

 for the corn. Not all of the oat pots are represented in-, 

 the fourth column of the table, for the reason that a' 

 number of pots carried peas instead of corn as the- 

 second crop; the cowpea results are given in a separate- 

 table. Apparently, tlic corn was slightly benefited by 

 the previous application of dihydroxystearic acid; 

 however, the difference between the yields from the 

 pot with complete fertilizer and the pot with dihy- 

 droxystearic acid in addition to the complete fertilizer- 

 is most likely due to slight soil inequalities, or to un- 

 avoidable errors, rather than to any benefit derived 

 from the special material added. Certainly, there is 

 no indication that dihydroxystearic acid is injurious 

 to corn or oats, under the conditions of tliis experiment. 

 The tabulated results follow: 



