744 CONTRIBUTIONS TO OUR KNOWLEDGE OF SOIL-FERTILITY, vii.-xi., 



a solution in olive oil being used in cases of scabies. Molten 

 naphthalene dissolves paraffin, grease-paint, unguentum resinse, 

 etc., and it acts, therefore, much as a volatile disinfectant. That 

 its antiseptic value is exceedingly poor, is evident from the 

 numbers of bacteria obtained in the experiments. This, however, 

 applies only to the quantities taken; a larger quantity might 

 show a disinfecting action. Small quantities of certain poisons, 

 such as ether, carbon bisulphide, potassium bichromate, copper 

 sulphate, etc., have a stimulating influence upon bacterial growth, 

 while certain others have not;* and it is possible that the naph- 

 thalene, in the experiment, exerted an accelerating action. 



The great multiplication of Bad. putidum, in the first experi- 

 ment, points to the probability that naphthalene will induce an 

 increased ammonification. To prove this, an experiment was 

 made by adding two grms. of dried blood to 200 grms. of dried 

 garden-soil, and adding a soil-suspension, made by shaking 100 

 grams of raw soil with a litre of water. With this, the moisture- 

 content was made up to 19%. The bottles, containing the soil, 

 stood upon the laboratory-bench for seven days, when they 

 received two grms. of copper sulphate, and 500 c.c. of water. 

 They were shaken 50 times, at hourly intervals, for a day, 

 allowed to rest overnight, and the supernatant liquid filtered in 

 the morning. The ammonia was determined, in the usual way, 

 by distilling with magnesium oxide. The numbers are the average 

 of three, and sometimes of four tests. 



Experiment iii. 



This unexpected lowering of the ammonification led to another 

 experiment being made. 



* Fred, Centrlbl. f. Bakt., 2te Abt., 31, 185. 



