22 
Journal of Agricultural Research 
Vol. VII, No. i 
solution were at once taken for determinations of dry weight, phosphorus, 
nitrogen, carbohydrates as reducing sugars before and after hydrolysis, 
and ash. 
The following determinations were then made upon fractions i and 2: 
Dry weight, ash, total phosphorus, total nitrogen, ammonia (in fraction 
2) , carbohydrates (as reducing sugar before and as invert sugar after 
acid hydrolysis in fraction 2; as hydrolyzable, polysaccharids in fraction 
3) , and total acids (in fraction 2). Details of the determinations follow. 
Dry weight. —The dry weight was ascertained in the case of fractions 
1 and 2 by taking an aliquot part of the solution, evaporating to con¬ 
stant weight in a previously weighed platinum or porcelain dish at 102° 
to 105° C., weighing, and calculating the total weight from the results. 
Fraction 3 was weighed entire after drying to constant weight in the 
tared diffusion thimbles in which the extraction had been carried out. 
Ash. —Ash was determined upon the portions of fractions 1 and 2 
which had been taken for dry-weight determinations, and upon an 
aliquot' of fraction 3. The procedure was the same in all cases. A 
preliminary test determined the presence or absence of free acids; if 
such acids were present, the sample was neutralized with sodium hydroxid 
and a correction for the sodium chlorid thus formed was made in the 
final weighings. The samples for ashing were transferred to previously 
dried, weighed porcelain crucibles, dried to constant weight in the oven, 
weighed, then placed within larger nickel crucibles. The contents were 
very gradually charred over a low flame, and finally burned to constant 
weight, averages of duplicate or triplicate samples being taken as true 
readings. 
Total, phosphorus. —Determinations were made by the Neumann- 
Pemberton method as described by Plimmer (16, p. 543) and by 
Mathews (13, p. 893-895). The method consists essentially in the 
conversion of organic to inorganic phosphates by the addition of con¬ 
centrated sulphuric acid and nitric acid, conversion of the phosphates 
into ammonium phosphomolybdate, dissolving the phosphomolybdate 
in a known excess of sodium hydroxid, and titrating the reduction in 
alkalinity of the sodium hydroxid with sulphuric acid. Determinations 
of inorganic phosphorus were attempted, employing the usual methods, 
but the amounts were so small—in no case amounting to 4 mgm.—that 
separate determinations were abandoned. 
Total, nitrogen. —Nitrogen was determined by the employment of 
the Gunning-Arnold modification of the Kjeldahl method. By reason of 
the very small amount of nitrogen present in fraction 2, the original 
intention to separate the nitrogenous constituents of the fraction into 
proteoses, peptones, polypeptids, amino acids, and nitrogen bases by 
separate determinations was abandoned. Accuracy in such determina¬ 
tions would have necessitated the extraction of very large amounts of 
material, which was impossible in the limited time available for the work. 
