24 BULLETIN 158, U. S. DEPARTMENT OF AGRICULTURE. 
estimated, and the extent of the hydrolysis of the original proteins 
was determined. It was also shown by this method that the proteose- 
like compound was composed of acid amide radicals, diamino ^.cid 
radicals, especially lysine, and monoamino acid radicals, particu- 
larly the monoamino acids which contain non-amxino nitrogen. 
The question of the availability of nitrogen is discussed and from 
a consideration of the amount and the physiological action on plants 
of the different forms of nitrogen present in the fertilizer it is con- 
cluded that the water soluble nitrogen of this fertihzer should have 
an availabihty equal to or greater than the nitrogen of dried blood, 
or other high-grade fertilizers. These results are in accord with the 
results obtained by the plant method of determining availability. 
The general chemical principle which miderhes the method for 
rendering available the nitrogen contained in most trade wastes, 
which are to be used as fertihzing materials, is shown to be either 
partial or complete hydrolysis of the protein of the wastes by any 
suitable means. 
The more complete the hydrolysis the more available the nitrogen 
in the fertilizer becomes, since the products of complete hydrolysis 
of proteins are not only utilized by the plants themselves as nutrients 
but they are more easily ammonified when placed in the soil than are 
the more complex compounds, such as peptones, proteoses, and the 
proteins themselves. 
This investigation aims only at an explanation and exposition of 
the general chemical principles involved in the treatment of trade 
wastes and other organic material to render the nitrogen contained 
therein more available for agricultural purposes. It does not aim to 
present the research methods here employed as general methods for 
analyzing such fertihzers, nor can the quantitative figures obtained 
be expected to apply to all products of similar manufacture, for the 
reason that the different kinds of nitrogen compounds will necessa- 
rily show different proportions according to the nature of the mate- 
rials which enter iato the mixture. 
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