70 Manganese in Land and Fresh Water Mollusca. 



is foulid rather abundantly in tea, coffee, tobacco and wine,, 

 and in this way passes pretty freely into man ; it is not, however,, 

 absorbed, but excreted in the faeces, and is present in human 

 tissues in very small traces 1 ; hence, in our anthropomorphic 

 way, we have given it less attention than it probably deserves. 

 P. Pickard 2 says that it is universally present in all orders 

 of plants, and points out that animals have much less ; fungi 

 and lichens have most and mosses much. P. Q. Keegan 5 

 notes its occurrence in a number of wild English plants. The 

 occurrence in mammals has been investigated by G. Bertrand 

 and F. Medigreceanu 4 ; the liver generally has most and o-i 

 part in ten thousand is a high figure, other tissues showing per- 

 haps only a twentieth of that. The same authors 5 examined a 

 number of invertebrates and note that specially large amounts 

 were found in Limncea stagnalis, Littorina littorea and Pecten 

 jacobmts, less in Helix hortensis, Unio sinuatus and half-a-dozen 

 other, marine mollusca. Bertrand 6 has advanced the view that 

 manganese salts play an important part as oxidising ferments, 

 though the idea has not been without objectors 7 ; he also 

 showed that Aspergillus will not develop conidia in the absence 

 of manganese. 8 Contino 9 found manganese always present 

 in Italian soils from traces to 0-3 per cent. It is present in 

 traces in many waters, especially mineral waters 10 ; the Buxton 

 thermal water, for example, contains o*ooi in ten thousand, 

 and the mud deposited by it 51 per cent. 11 



The meaning of the prevalence of manganese in plants I 

 would not venture to indicate ; possibly it expresses nothing 

 beyond the fact that the element is universally present in small 



1 E. Maumene Comptes Rendus, Vol. XCVIII. (1884), pp. 845, 1056 and 

 1416 : Bull Soc. Chim., Vol. XLII., p. 305 : sec also experiments by 

 Bertrand, Comptes Rendus, Vol. CLV. '(1912), p. 1556. 



2 Comptes Rendus, Vol. CXXVI. (1898), p. 1882 : unfortunately no 

 quantitative data are given. 



3 The Naturalist 1909, p. 430; 1910, pp. 177, 321 ; 1911, pp. 222, 418. 



4 Comptes Rendus, Vol. CLIV. (1912), pp. 941, 1450; Bull. Soc. 

 Chem. (4) Vol. XI. (1912), p. 857 ; Ann. lust. Pasteur, Vol. XXVI. (1912), 

 p. 1013 ; Vol. XXVII. (1913), p. 1. 



5 Comptes Rendus, Vol. CLV. (1912), p. 82. 



6 Ann. Agron., Vol. XXIII. (1897), p. 285; Comptes Rendus, Vol. 

 (XXIV. ( 1 y < > 7 ) , p. 1355 (see also p. 1349) ; also G. M. Piccinini, Arch. ital. 

 de Biol., Vol. LVIII. (1912), p. 360 ; on its share in the familiar blueing 

 of broken boleti, see Aim. lust. Past., Vol. XVI. (1902), p. 184. 



1 see Oppenheimer, Handbuch der Biochemie Suppl., 1913, p. 157. 



8 Comptes Rendus, Vol. CLII. (191 1), p. 225 ; Vol. CLIV. (1912), 

 pp. 381 and 616 ; Bull. Soc. Chim., Vol. X., pp. 212, 347, 400 and 494. 



9 Staz. sperim. agrar. itul., Vol. XLIV. (1911), p. 51. 



!0 F. Jadin and A. Astruc, Comptes Rendus, Vol. CLVII. (1913), p. 338 ; 

 sec also the analyses of mineral waters in A. Albn and C. Neuberg, Physiol. 

 11. Path, der Mineral stoffwechsels, 1906, and Data 0/ Geochemistry passim. 



H J. C. Thresh, Examination of water and water supplies, cd. 2. 1913, 

 pp. 124, 381 and 409. 



Naturalist, 



