EXPERIMENTAL WORK WITH RAW ROCK PHOSPHATE. 15 
Forbes and Fritz! suggested the introduction of floats into the 
silo in order that the fermentation process and the subsequent pass- 
ing of the ensilage through the animal’s body would aid in rendering 
the rock phosphate more soluble. The following table gives a 
summary of the analytical results obtained by these investigators. 
TaBLE VI.—Phosphorus in silage corn with and without added floats, and in 
silage made therefrom. 
Average content of phosphorus on water-free basis. 
Material. Water 
Total Water Citrate aS ores soluble plus 
soluble. soluble. 5 orth nC iL citrate 
soluble. 
a Et 
Per cent. Per cent. Per cent. Per cent. Per cent. 
0. 207 0. 149 0. 021 0. 083 g 
Untreated green silage corn.......-...-.--- 0.170 
Silage from untreated corn..........---.--- 224 - 160 - 008 e1ll - 168 
Green silage corn plus floats.........--.--- -371 . 136 - 061 172 .197 
Silage from treated corn.-..........-----.. . 384 . 157 . 060 SBS 217 
If the total quantity of phosphoric acid in the material is consid- 
ered, it will be seen that the fermentation process actually decreased 
the percentage of water-soluble plus citrate-soluble phosphoric acid 
present in the silage corn. Fermentation also produced little or no 
effect on the citrate solubility of floats mixed and charged to the silo 
with the corn. The amount of phosphate dissolved by a 0.2 per cent 
solution of hydrochloric acid, however, was considerably increased by 
the ensilage process. If this were an index of availability (an as- 
sumption which is hardly warranted) the mixing of phosphate rock 
with ensilage might be considered good practice. 
Mooers,? however, carried this investigation somewhat further and 
actually determined the citric-soluble phosphate in the dung of ani- 
mals fed with ensilage treated with floats, comparing the results with 
the dung of similar animals fed with untreated ensilage. 
The treated ensilage was produced by charging the silo with finely 
ground rock phosphate and corn at the rate of 2 pounds of the former 
to 100 pounds of the corn. It was assumed that the increased amount 
of total phosphoric acid in the dung of the animals fed with the 
treated ensilage was due to the rock phosphate in the ensilage. In 
order to have a check on the effect of fermentation and the subse- 
quent digestive process on the solubility of the phosphate, an 
amount of rock phosphate equal to that in the dung produced from 
the treated ensilage was added to the dung produced from un- 
treated ensilage. The results of this investigation are summarized 
in Table VII. 
1Jour. Ind and Eng. Chem., 6, 222 (1914). 
2 Jour. Ind. and Eng. Chem., 6, 487-8 (1914). 
