FERTILIZERS. 621 



tion on horse manure. In one series the manure contained from 80 to 

 82 per cent of moisture, in the other from (5 to 68 per cent. To each 

 100 gin. of the manure well supplied with denitrifying organisms from 

 5 to 25 gm. of the powdered sulphate was added, the powder being inti- 

 mately mixed with the manure. From time to time nitrate bouillon was 

 inoculated with particles of the manure. The culture experiments indi- 

 cated that in order to destroy the denitrifying organisms it was neces- 

 sary to mix at least 5 per cent of the powdered sulphate with the manure, 

 provided the manure contained at least 05 to 70 per cent of moisture. 

 When the amount of sulphate was increased to 20 to 25 per cent all 

 organisms in the manure were killed. As a rule the sulphate was more 

 effective in moist than in dry manure. 



Another series of experiments was carried out with moist (80 per 

 cent of water) and dry (05 to G8 per cent of water) manure in layers 1, 

 2, and 4 cm. thick, the sulphate being spread over the surface of the 

 manure in layers from 1 to 2 mm. thick. The time required for the 

 powder to be absorbed by the manure and for the organisms to be killed 

 depended upon the thickness of the layer of the manure and the amount* 

 of moisture present. In the thin layers the organisms were completely 

 destroyed in 24 hours, while in the thick dry layers they were still active 

 at the end of 12 days. It appeared that in the case of the moist manure 

 10 per cent of the powdered sulphate was sufficient to insure complete 

 destruction of the denitrifying organisms, while in the case of the dry 

 manure 15 per cent was necessary. 



In a third series of experiments 100 gm. portions of manure were 

 treated with 2.5, 5, and 10 per cent solutions of the preservative. In 

 this case 40 gm. of 5 per cent solution (2 gm. of the sulphate) was suf- 

 ficient to destroy the organisms in 100 gm. of manure both in the dry 

 and moist condition. 



Culture experiments similar to those with the denitrifying organisms 

 were made with the germs of Rothlauf and Schweineseuche. These 

 experiments indicated that 0.44 to 0.5 per cent of the sulphate was suffi- 

 cient to kill these organisms. 



Two sprinklings with a 5 per cent solution of sulphate is believed to 

 be the most practicable and effective means of destroying both denitri- 

 fying organisms and disease germs in manure. 



An analysis of the sulphate used is given which shows that it con- 

 tained 60.18 per cent of ferrous sulphate, 5.4 per cent of free sulphuric 

 acid (S0 3 ), 5.3 per cent of ferric sulphate, aud 1.32 per cent of water 

 and insoluble residue. 



On denitrifying organisms, O. Kunnemann (Landw. Vers. Stat, 50 

 (189*), Wo. 1-2 pp. 65-113). — The author reviews the literature of the 

 subject, and reports in detail experiments in preparing pure cultures of 

 denitrifying organisms from horse and cattle manure, from straw, and 

 from different kinds of soils. The organisms isolated are described, 

 and their behavior in different culture media and iu the presence of 



