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Fehling solution. These extracts then, seemed to contain organic 
acids and substances of the nature of sugars, resulting possibly 
from the decomposition of the cellulose, etc., left in the soil by 
previous plant growths. 
We undertook a closer chemical study of the extracts of heated 
and unheated soils from New York, Massachusetts and North 
Dakota. Parallel determinations were made of the total soluble 
matter, the organic matter, and the inorganic matter in soil 
extracts prepared in various ways. In general, we found that 
the extracts of heated soils contained from six to fifteen times 
as much soluble matter as did the same soil before heating and 
further, the organic matter seemed to be increased to a greater 
extent than was the inorganic matter. The. increase of soluble 
materials seemed to bear some relation to the amount of organic 
matter in the soils. The extract of one sample of North Dakota 
soil contained one thousand parts per million of soluble mat- 
ter before heating, but showed ten thousand eight hundred 
parts per million after heating. The facts already referred to, that 
upon standing, the heated soil gradually lost its properties favor- 
able to the growth of Pyronema and also that unheated soil could 
not be made favorable, even by the additions of large amounts of 
heated-soil extracts, were studied quantitatively and it was 
proved that when unheated soil was saturated with heated-soil 
extracts and allowed to stand, the latter were reduced to the 
same colorless state with almost exactly the same chemical com- 
position shown by ‘extracts of unheated soils. 
e ash of the different extracts was examined to determine 
ash of heated- and unheated-soil extracts (from North Dakota 
soil) contained calcium, magnesium and potassium, largely in 
the form of sulphates, along with some iron, sodium, manganese, 
silica, etc. From the known stimulating effects of calcium, and 
to a less extent of magnesium, one might say that the inorganic 
substances of the various soil extracts, as well as the organic 
constituents, may play a part inthe growth of Pyronema upon 
heated soils. 
As this work was being prepared for publication we found that 
