4 MINERAL CONSTITUENTS. 



detected in human gall-stones, (in one instance there was found 

 as much as 0*3^^ of the protoxide of manganese,) and traces of 

 it have been observed in the urinary calculi of the graminivora. 



5. Silica has been found in small quantity in the enamel of 

 the teeth, in bone, urine, lu'inary, intestinal, and biliary calculi, 

 hair, and saliva. It is found in considerable quantity in the 

 excrements, the amount varying with the nature of the food. 

 In the sheep the excrements have been observed to contain as 

 much as 6-0^ of silica. 



6. Alumina. Traces of this substance were detected by 

 Yauquelin, in human bones; it has been found in considerable 

 quantity in fossil teeth and horns. The circumstance of its 

 being an occasional constituent of intestinal concretions coincides 

 with Lehmann's experiments, in which he found that when 

 alumina was introduced into the system, it was carried off by 

 the faeces. 



7. Ai'senic was recently stated by Orfila to be a normal consti- 

 tuent of human bone. This opinion has, however, since been 

 Avith drawn, and there is little doubt that there was some fal- 

 lacy in his experiments. 



8. Copper is considered by Devergie, Lefortier, and Orfila, to 

 be a normal constituent of all the soft parts, as well as of the 

 blood of healthy persons. Devergie"' analysed the Adscera of 

 five persons and found it in every instance. It has also been 

 found in the sweat. 



9. Lead has been found by these chemists in the same cases 

 as copper. 



10. Ammoniacal salts. In the blood, lymph, chyle, and milk, 

 there are no appreciable ammoniacal salts. They have been 

 observed in some cases in the sweat, and they occur in a small 

 proportion in the urine. 



' The notation g represents per ccntagc. 



* These observations have recently been confirmed by M. Barse, who succeeded in 

 finding both copper and lead in the bodies of two persons to whom they could not 

 have been given for poisons. It seems from the analyses of Signer Cattanei that 

 neither of these metals exists in the boilics of new-born children or infants ; and 

 Rossignon has recently pointed out the sources from which the bodies of adults pro- 

 l)ably derive their copi)er. He has found this metal in gelatin, chocolate, bread, 

 coffee, sugar, &c. 



