Bacteriological Studies of the Fixation of Nitrogen. 
dead or dying (See fig. 3, Page 23) and beyond these the burning 
seemed to stop. However, twelve rows farther back on the higher 
ground I discovered a single tree which was firing. There was a 
little white alkali nearby but no sign of any brown or black color. I 
took Sample No. 29 from the surface of the soil near this tree. So far 
as I could see, this was the only tree in that part of the orchard which 
was suffering at this time. I visited this same spot January 31, 1911, 
and the spectacle that greeted me was awful, to express it mildly. 
Where three months before there was but a single tree affected, there 
Fig. 3. Section of an orchard killed by nitre. Photographed October 29, 1910. 
were now six to eight acres involved. The soil was brown and very 
mealy. The orchard manager informed me that most of this change 
had followed the last irrigation of the orchard which was given about 
December 1, 1910. He related that three or four days after he 
had finished irrigating, he noticed a dark brown, oil-like spot ten 
inches in diameter near the tree from which sample No. 29 was taken 
and that after twenty-four hours this had increased to twenty-four feet 
in diameter by actual measurment. In spite of all efforts to break 
down this testimony by cross examination and conservative sugges¬ 
tions, my informant held firmly to the original statement declaring 
that there was absolutely no exaggeration. This particular instance 
most certainly holds all previous records for rapid progress. It was 
