368 
Journal of Agricultural Research 
Vol. XI, No. 8 
At first indications were afforded by this method that a larger propor¬ 
tion of the total phosphorus was secured from turnips grown on soil well 
supplied with available phosphorus than from turnips which had been 
grown on soil quite deficient in this ingredient. This was considered to 
be an important differentiation regardless of whether or not the determi¬ 
nation could be considered strictly that of inorganic phosphorus, since 
it appeared to furnish an additional indirect method for securing informa¬ 
tion regarding the relative amount of available phosphorus at the dis¬ 
posal of the plant. 
However, according to subsequent work with the method by other 
analysts on turnips grown in a number of different years, there were 
frequent failures to find any marked increase in the proportion of inor¬ 
ganic to total phosphorus in the turnips as a result of the application to 
the soil of liberal amounts of available phosphorus, although the crop 
and the percentage of total phosphorus in the same were much increased. 
It was found in some instances that a small excess of ammonium 
hydroxid resulted in a considerable increase of inorganic phosphorus in 
the precipitate by barium chlorid. There was no certainty as to whether 
this increase represented a portion of the inorganic phosphorus not pre- 
cipitable from a neutral solution, or whether the excess ammonia had 
caused a dissociation of phosphorus from organic combinations. By 
adding an excess of ammonia, on the assumption that all of the inorganic 
phosphorus was not precipitable in a neutral solution, practically the 
total phosphorus was frequently precipitated. 
It has already been shown that phytin was absent from the juice, 
and it may well be questioned whether the small amount of phosphorus 
usually contained in the rather voluminous precipitate formed upon the 
addition of alcohol to the acidulated juice is an essential constituent of 
the same or has merely been dragged down by it. 
If it is true that nearly all the phosphorus of the juice is inorganic, as 
seems likely to be the case, at most only the determination of total 
phosphorus in the juice could be of advantage for the purpose in mind; 
furthermore the determination of total phosphorus in the juice would 
be no more useful than that in the entire turnip unless differences in 
the amount of available soil phosphorus influence the composition of 
the juice more than of the rest of the turnip. 
Such an influence seemed reasonable, and some evidence for that idea 
has been secured. At other times, however, an increase in the amount 
of available soil phosphorus seems to have increased the phosphorus of 
the juice no more than of the rest of the turnip. 
Looking upon the inorganic phosphorus in the juice as being the 
excess above that required for the essential tissues, one would hardly 
expect to find much phosphorus in this form in turnips which had made 
only a small growth because insufficient soil phosphorus was available. 
Possibly, however, the turnip conserves a certain proportion of inorganic 
