BY R. GREIG-SMITH. 



'43 



As 0-1% is approximately equivalent to 27 cwts. per acre, the 

 quantities added were excessive, but they have shown that naph- 

 thalene and thiosulphate have a decided effect upon the numbers 

 of bacteria. In the case of the naphthalene, the amount used 

 was about eighty times that recommended, assuming that it was 

 thoroughly mixed with the soil. The sulphur was about ten 

 times that used by Boullanger in his experiments. The prevail- 

 ing bacterium, in the six days' naphthalene-test, was Bad. 

 putidum (85 millions). 



A second experiment was prepared, using varying quantities 

 of naphthalene and thiosulphate. The soil was an alluvial, and 

 received raw soil-extract equivalent to 1% of soil. The bottles 

 were stored in the laboratory. 



Experiment ii. 



In this soil, the thiosulphate does not show the difference over 

 the control that it did in the previous experiment with garden- 

 soil, while the behaviour with naphthalene is confirmed. The 

 different action of thiosulphate, in the two kinds of soil, may 

 possibly be explained by the greater agricere-content of the 

 garden-soil, which is comparatively rich in this substance, while 

 the alluvial soil is comparatively poor. Seymour Jones* says 

 that sodium thiosulphate possesses the property of being able 

 to remove grease from pelt or from leather, and it may have the 

 same effect, therefore, upon the organic matter of the soil. 



Naphthalene is used as an insecticide, and to disguise disagree- 

 able odours, such as occur in urinals, etc. It is soluble in oils, 

 * Journ. Soc. Chem. Ind., 1912, 1130, abstract. 



