128 Argyll Campbell 



The bones were scraped clean and then powdered as iinel}- as possible. 

 The seal bones were very tough compared with the others. 



Volumetric methods were employed in the estimation of calcium, 

 magnesium, and phosphorus in the humerus, and in portion A of the rib ; 

 with those exceptions gravimetric methods were employed for analyses of 

 the ash. 



The following is a short sununary of the method used to estimate each 

 constituent. 



Water. 



The powdered bone was dried at 1 1 0'' C. This caused a loss of some of 

 the water only. During incineration (see below) the bone lost more of its 

 weight than that accounted for as protein, fat. and water driven off at 

 110° C. As will be seen in the tables, I have assumed this loss to be 

 water driven off at a temperature higher than 110" C. 



Organic Substances. 



Protein. — For qualitative examination the salts were first removed by 

 dilute hydrochloric acid and the residue analysed for mucin and collagen. 

 For quantitative estimation the total nitrogen was obtained by Kjeldahl's 

 method. The average of Hoppe Seyler's percentages of nitrogen in all 

 proteins (1() per cent.) was used in calculating the amount of protein in 

 the bone. 



Fat was estimated by extraction with ether (Soxhlet's method). 



Inorganic Substances. 



Total Ash was estimated by incineration in a platinum crucible, with 

 subsequent addition of ammonium carbonate to recarbonate the lime. 



Chlorine, Sulphur, and Fluorine. — Onl^^ qualitative tests were 

 made. 



The following volumetric methods were employed : — 



Calcium. — The powdered bone was submitted to combustion by acid 

 incineration. The calcium was precipitated as calcium oxalate, dissolved 

 in acid, and titrated against potassium permanganate. 



Phosphorus Pentoxide.— After incineration the phosphorus was pre- 

 cipitated by ammonium molybdate. The precipitate was dissolved in excess 

 of N/2 sodium hydroxide, and the excess estimated by titration against 

 N/2 sulphuric acid. 



Magnesium. — After acid incineration and removal of the calcium as 

 calcium oxalate, the magnesium was precipitated as ammonium-magnesium- 

 phosphate. The precipitate was dissolved in acetic acid and the solution 

 titrated against uranium nitrate. The magnesium was estimated from the 

 amount of phosphate present. 



The following gravimetric methods were employed : 



Carbon Dioxide.— The carbonic acid was liberated by dilute hydro- 



