34 CYANAMID — MANUFACTURE), CHEMISTRY AND USES 



tive substance. Now soil in the presence of secondary products 

 may be expected to act similarly to soil in the absence of 

 secondary products, that is, the soil should determine in flask 

 3 about 7 per cent, of decomposition more than occurred in 

 flask I. The presence of nutritive substance is therefore 

 probably in this case the controlling factor, but not nutritive 

 substance alone/ but nutritive substance in combination with 

 soil and cyanamide derivatives. It is quite possible that a 

 bacterial decomposition that does not take place in the pres- 

 ence of cyanamide alone may take place if other nitrogenous 

 substances are present which are capable of being attacked 

 by bacteria. In fact, Ulpiani determined by separate experi- 

 ments that the soil bacteria employed by him were not able 

 to decompose pure cyanamide, but that they grew very readily 

 in impure dicyandiamide solutions, while the experiments of 

 Kappen show that micro-organisms do take part in the decom- 

 position in the presence of nutrient solutions and, with the 

 exception of special fungi, in non-sterilized soil. The effect 

 of micro-organisms and of glucose used as a nutritive sub- 

 stance is shown by the following experiment of Kappen.^ 



One hundred grams of a sand soil of low activity was treated 

 with 50 cc. cyanamide solution containing 33 mg. of cyanamide 

 nitrogen. The same treatment was given another 100 grams, 

 but glucose was added. In another case no glucose was added, 

 but the soil was inoculated with cyanamide-splitting clado- 

 sporium, a special fungus, occurring in some soils. The sub- 

 sequent content of cyanamide nitrogen is shown in the fol- 

 lowing table: 



Without 

 Cyanamide glucose 



nitrogen in With Without with 



milligrams glucose glucose cladosporium 



Applied 33-00 33.00 33.00 



Analysed immediately 31-75 32.04 32.48 



After I day 25.87 23.70 — 



After 2 days 23.52 21.16 4.70 



After 3 days 19-69 17-93 0.00 



After 7 days 8.33 12.55 - 



After 9 days 0.00 10.29 — 



* Zentr. fur Kunstdiinger Ind. XVII, 251, 191 2. 



