ACTION OF ANTISEPTICS 



logical functions of the crop, and thus lead to an increased 

 yield, but the fact that the good effect lasts for some time 

 after the compounds have evaporated, militates against 

 the acceptance of this view. 



The investigations of Hiltner and Stormer, Pagnoul, 

 Hentze, Russell and Hutchinson show that the beneficial 

 action of antiseptics is connected with alterations in the 

 nature and number of the living organisms of the soil. 

 Hiltner and Stormer showed that the bacterial content 

 was reduced at first by the application of carbon disul- 

 phide, but later the numbers increased enormously. 

 Untreated soil, containing 9! millions of bacteria per 

 gram, contained comparatively few immediately after 

 treatment, but after the lapse of a month or less, the 

 number rose to about 50 millions per gram. They 

 found that the nitrifying and denitrifying organisms 

 were destroyed almost completely, and did not again 

 develop to any extent unless fresh inoculation occurred. 

 Species of Streptothrix, which composed about 20 per 

 cent, of the total bacterial flora, were reduced, but the 

 non-liquefying organisms increased very rapidly. 



Similar marked increase in numbers of bacteria in 

 partially sterilized soil was observed by Russell and 

 Hutchinson, and found to be correlated with proportional 

 increase in the production of ammonium compounds. 



NUMBER OF ORGANISMS PER GRAM OF SOIL. 



