32G ox UKXTAL IXCRI'STATIOXS, 



ANALYSES OF DENTAL INCRUSTATIONS. Cement layer 



(Ciiisla pe/rosa) 





C 



Lime (CaO) ■10-75 28(X) 29-38 37-75 37-00 46-13 47-50 35-119 3(i-21 



Mao-nesia (Mg O) 0-18 4-19 3-69 0-27 0-18 0-56 0.68 112 . 0-98 



Phosphoric oxide (Po O5) 34-73 26-.55 2817 29.33 2948 7-95 714 26-68 26-88 



Carbon (Uoxide (CO2) 1-32 1-45 1-10 2-70 2.88 22-65 1 ^^ 2-90 1-80 



Organic matter* 17-23 24-65 23-90 16-20 16-82 17-48 j " 23-54 24-74 



Water at 110° C. 5-38 11-03 10-30 11-65 10-40 3-85 2-63 9-35 8-66 



Sand 0-10 2-30 2-00 0-60 0-30 055 0-39 nil nil 



Undetermined and loss 0-31 1-83 146 1-50 2-94 0-83 0-03 0-72 0-73 



100-00 ia)-ai loo-oo lo-ooo loo-oo loo-oo loo-oo loo-oo loo-ai 



•Containini; nitrogen 1-20 1-48 0-71 



Sp. Gr. 2-317 2-025 2112 



Mikloulio-Maclay mentions that specimens of teeth similarly iiiornsted to 

 those which he describes were forwarded by F. A. de Roepstorff from the Xicobar 

 Islands to Professor Yin-how. Berlin. -t The deposit from these was analysed by 

 Salkowski, and the results published by Virchow. llu- following being the figures: — 



Water . 93 



Organic matter !) . iU 



Silica and iron oxide .87 



Iron phosphate 2.26 



Lime 45 . 24 



Magnesia .68 



Pliosphoric oxide 30.73 



(,'arbiin dioxide 4.87 



S):) . 70 

 This shows more lime and carbtm dioxide and consideraldy le.ss organic matter 

 than I found in the normal incrustation from hunuui teeth. Probably this is a 

 result of the addition of carbonate of lime from the lime-betelnut habit, but the 

 high phosphoric acid shows that essentially the deposit has been derived from the 

 saliva. The presence of so much iron phosphate is peculiar, and T am uniible to 

 explain it. I found no apiireciable iron in any of ray samples. 

 The analysis l)y Berzclius mentioned above, is thus stated :-- 



Eartiiy phosidiates 70.0 



Mucus 12.5 



Peculiar salivary matter 1.0 



Animal matter soluble in muriatic aciii 7.5 



100 

 There is no mention of water. It is probable that Herzelius merely ignited 

 and took the ash as "earthy phosphates," and the organic substances include 

 water. For a rough comparison it will suffice to consider the "phospliates" as 

 being tribasic phosphate of lime and to lump tou-etlior tlie orsranic substauces. 

 This would give: — 



tVerh. Berlin. (Jes. Anthrop., June, 1881. p. 219. 



