EDITORIAL. 605 



Professor Kiilin was the recipient of man}^ honors from the gov- 

 ernment and from various societies and associations. He was made 

 Geheimrat in 1882, and in 1903 was given the title of Exzellenz. 

 Orders were conferred upon him by his own and foreign govern- 

 ments; he was awarded the Liebig medal and the Prussian gold medal 

 for service to agriculture ; and he was made an honorary member of 

 a long list of societies and academies. 



Personally Kiihn was of a kindly, sympathetic disposition that 

 made him beloved as he was respected by all who came Avithin the 

 sphere of his influence. His relations with his students were 

 unusually close, and he was affectionately known among them as 

 " Father Kiihn." They united with a long list of his admirers in 

 honoring him in a public celebration of his seventieth birthdaj^ in 

 1895, and again on his eightieth birthday ten years later. His declin- 

 ing years were marked by a remarkable vigor and continuance of 

 activity. He accomplished well what in early life he set out to do, 

 and his name will long live in the institute to which he gave a world- 

 wide reputation. 



There has been great activity in recent years in the study of the 

 relation of bacteriological activity to soil fertility, and valuable con- 

 tributions have been made to the knowledge of this subject. These 

 studies are clearing up problems of soil fertility which chemical and 

 physical investigation had left obscure, and are showing how pro- 

 foundly soil processes are modified and controlled by bacteriological 

 action. 



Quite recently, Eussell and Hutchinson of the Rothamsted Experi- 

 ment Station have aroused a new interest in the subject through 

 reports of their studies of the effect of partial sterilization by means 

 of heat or volatile antiseptics upon the productiveness of soils. These 

 studies have been characterized by Prof. A. D. Hall, director of the 

 Rothamsted Station, as " the most notable addition to the theory of 

 the soil since the publication of Hellriegel and "Wilfarth's paper on 

 the nodule bacteria in 1886." 



These investigators found, in agreement with many others, that 

 the fertility of the soil can be greatly increased by heating or by 

 treatment with volatile antiseptics. It was observed many years ago 

 that treatment of vinej'ard soils with carbon bisulphid for the pur- 

 pose of destroying phylloxera resulted in an increased productiveness 

 which could not be entirely accounted for by the destruction of the 

 phylloxera. Dr. G. E. Stone, of the Massachusetts Experiment Sta- 

 tion, observed that steaming greenhouse soils to destroy nematodes 

 apparently increased the actual fertility of the soil. Dr. Bernard 

 Dyer reported the same result from steaming garden and greenhouse 

 soils. More recently Prof. T. L. Lyon and Mr. J. A. Bizzell, of the 



