128 



NATURE 



[July 28, 1910 



established, and also to render animals resistant to a 

 secondary inoculation, i.e. to dissemination and metastasis 

 formation. 



The immunity reactions to transplanted cancer are 

 throughout clearer and more easily studied than are those 

 of spontaneous cancer. The problems presented by spon- 

 taneous tumours are more delicate and elusive. The 

 methods effectual in normal animals against primary 

 inoculation with transplantable tumour, which, as men- 

 tioned above, also arrest the growth of growing transplanted 

 tumours and prevent successful re-inoculation in suitable 

 circumstances, have been without action on the continued 

 growth of the twenty-five spontaneous tumours on which 

 they have been tested, have failed to prevent recurrence or 

 dissemination, and have not yet prevented a successful 

 re-inoculation of the spontaneously affected animal with its 

 own tumour. The investigations must go on until a 

 higher degree of resistance can be obtained in this way, 

 or it may be that an entirely different method must be 

 sought. The expectation of ultimate success seems a fair 

 inference from the results obtained with transplanted 

 tumours which reproduce all the phenomena of growth and 

 dissemination of spontaneous tumours, and from the rare 

 but undoubted cases in which temporary arrest of growth 

 or total disappearance have occurred in spontaneous 

 tumours. 



The prospect is made the more hopeful by the discovery 

 of a method whereby an animal can be immunised by means 

 of one of its own tissues against a primary inoculation of 

 a tumour transplanted from another animal. This, again, 

 is a very different matter from immunising an animal 

 against its own tumour. Nevertheless, it illustrates how 

 much that was previously unsuspected is being revealed, 

 as step by step advances are made into yet unexplored 

 regions. Inquiries into the effects which the several 

 tissues of the body may have, either singly or in combina- 

 tion, in inducing protection are being made. 



Chronic Irritation and Cancer. 

 A practical result arises out of the association of various 

 forms of irritation with the development of cancer in sites 

 where more obscure influences can be excluded, especially 

 from what has been ascertained on the incidence of cancer 

 in native races practising peculiar customs, and on the 

 incidence of cancer in some animals. Experiment has 

 emphasised this relation, and has thrown light upon the 

 mechanism which makes the irritation effective, leading to 

 similar consequences, although the irritants themselves have 

 nothing in common. Recent legislation is thereby justified 

 in the interest of workers employed in circumstances ex- 

 posing particular parts of the body to chronic irritation of 

 peculiar kinds. In 1903-4 the feasibility of obtaining more 

 accurate information of the incidence of cancer in different 

 occupations was before the Statistical Sub-committee. The 

 progress made since renders such an investigation still 

 more urgent to-day. It must not be supposed, however, 

 that cancer has been proved to be always the result of 

 irritation. The mediate influence of irritation has only been 

 defined more closelv than ever before. 



MANG.\NESE MINING IN INDIA.^ 

 'T'HE many uses of manganese in the arts were known 

 long before the metal had itself been recognised. It 

 has been used since prehistoric times as a colouring 

 material, and by primitive Indian smiths as a flux and as 

 an alloy for hardening iron and bronze ; and its power as 

 an oxidiser now renders it one of the most important of 

 disinfectants, and a valuable chemical reagent. The metal 

 has an interesting, but uncertain, history ; the origin of 

 the name is doubtful, but it appears to have been first 

 used in the sixteenth century as a variant of magnesium, 

 from which it had not been separated ; and even after its 

 recognition as a distinct metal by Gahn in 1774, Berg- 

 mann still called it magnesium, though the name man- 



1 Memoirs of the Geologwal .Survey of India. Vol. xvxvii. The 

 Manganese-Ore Deposits of India. By L. Leigh Fermor. Part i.. Intro- 

 duction and Mineralogy. Pn xcvii + 2ii. Part ii., Geo'noy. Pp. •.,-;j-4o5. 

 P.irt iii.. Economic-; and Mining. Pp. 406-610. (Calcutta : Geological 

 .Survey. 1909.) Price 3 rupees each. 



NO. 2126, VOL. 84] 



ganese, derived from magn^sie by the reversal of two 

 letters, had already been used. 



Manganese is one of the most widely distributed of the 

 metals. According to Mr. F. \V. Clark it forms one- 

 thousandth of the earth's crust, and is the fifteenth of the 

 elements in quantitative hnportance. Mr. Fermor, accept- 

 ing the number of mineral species as 1000, reports that no 

 fewer than 130 to 140 of them contain manganese as an 

 essential constituent. The manganese minerals are especi- 

 ally conspicuous, as they are mostly found in decomposed 

 rocks upon the earth's surface; and as manganese salts 

 are easily dissolved, the metal is a common constituent in 

 the ash and latex of plants, and is found in the blood and 

 tissues of many animals. According to Penrose, the pro- 

 portion of manganese to iron in the human body is said 

 to be as i to 20. 



The increased use of manganese as an alloy has led to 

 a more active search for its ores, with the result that the 

 once important manganese mines of the south of England 

 have been closed owing to the discovery of much larger 

 supplies abroad. The manganese mines of India, accord- 

 ing to native traditions, supplied ores to the Phcenicians, 

 and the local smiths faced their anvils and hammers with 

 manganese steel, which they knew as kheri. It was not, 

 however, until 1892 that India began to produce manganese 

 ores for export, with the small contribution of 685 tons. 

 The ores are abundant in India, especially in the Central 

 Provinces and in the States of Hyderabad and Mysore, 

 and as the deposits are on the surface, and can be worked 

 by shallow quarries, the Indian output increased rapidly 

 until, for the years 1890-1906, it was second only to that of 

 Russia. In 1906, and possibly some later years, India has 

 taken the front place as a producer of manganese ores. 

 The other countries in order of yield are Brazil, Spain, 

 Turkey, Chile, France, Greece, the United States, and 

 Japan, while large quantities of manganiferous iron ores 

 are raised in the United States, Germany, and Greece. 



The manganese ores of India have frequent but short 

 references in geological literature, but little was l-cnown 

 certainly about them until after the discovery of their 

 economic importance. They have now been carefully 

 investigated by Mr. L. Leigh Fermor, of the Geological 

 Survey of India, and he has issued the result of his studies 

 in a monograph that forms a most important addition to 

 the geology and mineralogy of manganese. The Indian 

 mines have added several new species of manganese 

 minerals, amongst which the most important are hoUandi^f , 

 the crystalline form of psilomelane, and two new species 

 characterised by their striking pleochroism — juddite, a 

 manganese pyroxene, and blanfordite, the corresponding 

 amphiboie. Mr. Fermor also introduces new names for 

 two manganese garnets, grandite, an abbreviation for 

 grossular-andradite, and spandite, for spessart-andradite. 

 Coinmercially, the most important of the Indian species 

 are braunite and pyrolusite, which together produce 90 per 

 cent, of the output. 



Mr. Fermor 's memoir includes a detailed account of the 

 manganiferous minerals. The chemical composition of the 

 various species is re-considered, and the complexity of 

 many of them is shown by the elaborate general formulae, 

 by which alone they can be adequately represented. 



The Indian manganese ores are mainly found in the 

 pre-Cambrian rocks, though some interesting deposits of 

 secondary economic importance occur in the laterites. The 

 chief ores are associated with a varied series of igneous 

 rocks, which Mr. Fermor groups as the kodurite series. 

 They range from acid to ultra-basic varieties, all charac- 

 terised by being rich in manganese and manganiferous 

 minerals. Mr. Fermor describes in detail the petrography 

 of this interesting rock series. The kodurites are appar- 

 ently intrusive — though the evidence for this fart is 

 described as incomplete — into two series of Archean 

 gneisses. The first series consists of calcareous gneisses 

 and the second of the inetamorphic gneisses, which have 

 been described by Mr. J. T. Walker as the kondalite series. 



As usual with manganese deposits, the Indian mines are 

 still shallow, and the deposits are probablv very limited in 

 depth ; for they have been formed by chemical processes that 

 only take place near the surface. They are generally due 

 to the replacement of rocks by solutions containing man- 

 ganese. Mr. Fermor reports that many of the deposits 



