Pli(>f<plioriis. 371 



so great, but sufficiently striking to be evident at once; thus 

 per 100,000 parts of clay sub-soil we find in Victoria 66 parts 

 of phosphoric acid as against 159 jiiu-ts in America. Tlie 

 amount in Mallee soil is very low, namely, 47 parts per 100,000 ; 

 and Amcric;an and European authorities look upon 50 parts per 

 H 0,000 as the limit below which it is unprofitable to Avork the 

 soil. 



The objects of the following research were: — 



1. To ascertain whether plants could accommodate them- 



selves to a soil containing less than the average 

 amount of available phosphorus. 



2. To compare the phosphorus content of some typical 



Australian grown foods with the determinations of 

 phosphorus content in the same kinds of foods in 

 other countries. 



3. To determine the distribution and evolutionary signifi- 



cance of pliosphorus in muscle, Ijrain, exo- and endo- 

 skeleton of animals. 

 ■i. To obtain some quantitative data regarding the leak- 

 age of phosphorus from Victorian soils-. 



Methods. 



In all the estimations of phosphorus, except where specially 

 mentioned, the method used was a modification of the Neumann 

 method of phosphorus estimation (6), and was as follows: — 

 The substance, weighed in the fresh and then in the dry state, 

 was ashed. The ash weighed and dissolved in a small quantity 

 of nitric acid, diluted, precipitated with 10 per cent, ammo- 

 nium molybdate in presence of ammonium nitrate, the quan- 

 tities of these reagents being used in amounts such as are best 

 calculated to prevent precipitation of any molybdic acid, thus 

 when about 10 inilhgrams of pliosphoric anhydride were 

 roughly expected to be present, 4-5 c.c. of strong nitric wei^e 

 used to dissolve the ash, from 150-200 c.c. of water used to 

 dilute, 85 c.c. of 50 per cent, ammonium nitrate added, and 

 the solution then brought almost to Ijoiling point, 50 c.c. of 

 hot 10 per cent, ammonium molybdate Avere then added, and 

 the solution kept in motion for one minute, then allowed to 



10a 



