The Fertilising Influence of Sunlight

Abstract

WITH reference to Dr. Russell's remarks on this subject in NATURE of April 28, I should like to remark (1) that my point was not so much that toluene removed toxic material from the soil as that it rendered it insoluble. The question of washing out material from the soil was not raised by me. (2) and (3) Dr. Russell seems to beg the question by taking “fertility” and “bacterial activity” as synonymous. He has not, so far as I can find, proved that the addition to partially sterilised soil of an aqueous extract—or of a portion—of an untreated soil increases crop production (in contradistinction to soil fertility as indicated by bacterial activity and ammonia-production). If such is found to be the case, it would certainly require further experiment before it could be explained on the toxic theory.