53^ 



NATURE 



[June 15, 1911 



decomposition of nianganiferous silicates in crystalline 

 rocks. The stcond tjpo includes bedded ores ; their man- 

 ganese was derived from the silicates of crystalline rocks, 

 and was deposited in the sedimentary rocks and then con- 

 centrated ; this {^roup includes the Appalachian ores, the 

 most important in the United States. The two last groups 

 comprise the manganese minerals associated with the silver 

 ores of Leadville and other western mining fields, and the 

 deposits with the Jurassic radiolarian jasperoids of Cali- 

 fornia, which, according to Prof. Lawson, were deposited 

 by suboceanic springs. 



The chapter on the protean chemistry and uses of 

 manfjanese describes the introduction of manganese steel 

 in consequence of Hadficld's discovery that though the 

 addition of 5 per cent, of manganese renders steel brittle 

 and useless, the presence of about 12 per cent, produces a 

 metal so hard, tough, and nonmagnetic that it has very 

 important industrial applications. 



Maine and New Hampshire are Slates in which mining 

 ^ of sf'oondary importance, but Mr. W. H. Emmons' short 

 and interesting bulletin shows that ore deposits occur which 

 have some features in common with those in the adjacent 

 provinces of Canada. The geology is well known from 

 Hitchcock's memoir and the later researches of Dr. G. O. 

 Smith. The valuable minerals include gem-bearing pegma- 

 tites, which are not described in this bulletin, and some 

 pyritic veins and ores of lead, zinc, silver, copper, and 

 molybdenum. The basement of the area consists of meta- 

 morphic rocks, which are regarded as probably Archean ; 

 they are succeeded by sediments and volcanic rocks attri- 

 buted to the Cambrian ; the volcanic rocks were followed 

 or accompanied' by some igneous intrusions, beside which 

 ores were formed as contact deposits. These rocks were 

 then crushed to schists, at a date which is pre-Silurian, 

 "but how much older is not known." Granitic intrusions 

 followed in the Devonian. 



The most interesting ores are the pyritic bodies, which 

 here, as in other cases, give clear evidence of the depth 

 at which the rocks were foliated, for the change took place 

 where the ores were in the zone of fracture and the slates 

 were in the zone of flow. 



The bulletin contains some excellent illustrations of the 

 microstructure of the ores. One of the most novel is of 

 molybdenite ore from the Catherine Hill Mine. It is given 

 to illustrate the author's view that the molybdenite was a 

 primary constituent of the granite, and that the felspars 

 floated in the liquid molybdenite ; whereas the photograph, 

 showing that the sulphide is permeating the large crystal 

 of orthoclase and that a thin felspathic tongue with a 

 disconnected end projects into the solid ore, rather indicates 

 the secondary nature of the molybdenite. 



J. W. G. 



RECENT CONTRIBUTIONS TO THE STUDY 



OF HEREDITY.' 

 (OpROTOZOA have as yet played but little part in the 

 literature of heredity, and there are even some 

 writers who belittle and disparage the evidence afforded by 

 this group of animals on the ground that there is in them 

 no separation of germ-plasm from somato-plasm. On the 

 other hand, Jennings and Bateson have pointed out the 

 importance of following the behaviour of conjugating and 

 dividing Protozoa, since at such phases of life the pheno- 

 mena of heredity are seen in a simple form. It is 

 now known that this simplicity is deceptive. The proto- 

 zoon does not simply cleave into two daughter cells, but 

 first of all absorbs certain organs of its body, and after 

 dividing its substance between the two or more descend- 

 ants, leaves to them the further task of reforming these 

 lost organs and other parts afresh. Moreover, in such a 

 way is the cleavage carried out that the regenerating parts 

 required by each dai-.ghter cell are not optically sym- 



1 (i) " Euplotes Worcrsteri 11. Division." By L.E. Griffin. Philit>pine 

 Journal of Scienee, Vol. v. No. 6, Decpmher. io»o. Pp. 322-i3'i + 5 pUtes. 



(a) "Experiments with Prosophila Ampelophila concerning Evolution." 

 By F. E. I.utz. Pn. iii+40. (Carnegie Institution, Wzshington : Publica- 

 tion No 14-?, March, igii.) 



(■?) " On Germinal Transplantati -n in Vertebrates." By Prof. W. E. Castle 

 and I. C Phillips. Pp. af. {IHd. : Publication No. t/4, Marrh. 1911. > 



(4) " The Maturation of the Ege of the Mouse." Bv (.A. Lone and E. 

 L. Mark. Pp. iv+7a+6 plates. (/btW. : Publication No, 142, April, 1911.) 



:to. 2172, VOL. 86] 



metrical. One may form a " head," the other a " tail,"' 

 from what was the middle of the parental body. In other 

 words, a dividing protozoon exhibits heredity under th 

 form of alternate symmetry. 



In the first paper on our list, this form of hcredit} .. 

 dealt with as fission. The particular animal studied is a 

 species of Kuplotes, a genus of ciliatc infusoria commonly 

 found on Hydra. Before division takes place, a new 

 mouth is formed, independently of the existing one, by a 

 depression of the ectoplasm, and a modification of its 

 substance develops into a definite peristome. Meanwhile, 

 the meganucleus elongates and becomes segmented into 

 definite regions. The old cirri are gradually absorbed, and 

 are replaced in the daughter cells by new structures. The 

 author describes these changes in great detail, and 

 promises another contribution upon the changes in 

 Euplotes during conjugation. 



{2) The pomace-fly, Drosophila, has been the subject of 

 much recent investigation in America owing to its short 

 life-history and the ease with which it breeds in captivity. 

 The present paper, by Mr. V. E. Lutz, deals with the 

 inheritance of abnormal venation in the wings of this fly. 

 The facts, put very briefly, are that in wild specimens a 

 few additional veins are occasionally, but rarely, met with, 

 and the experimental evidence shows that in a large 

 number of matings the percentages of such abnormally 

 veined specimens are: — normal X normal, 96 per cent.; 

 abnormal c? X normal 9 , 358 per cent. ; normal <S X 

 abnormal O, 5.^.7 per cent.; abnormal J X abnormal J, 

 85-9 per cent. Discussing these remarkable increases in 

 the ratio of abnormal to normal offspring, the author 

 suggests that in all Drosophila gametes there is a factor 

 tending to produce additional veins, but that its effects are 

 often obscured, and only become visible in what may be 

 called the upper part of its range. Especially interesting 

 is the rise in the intensity of this factor when an abnormal 

 strain is selected for breeding, and its rise and subsequent 

 fall in a normal strain. -Another point of importance is 

 the observation that normally veined flies select normal 

 mates when given a choice of both kinds. Mr, Lutz also 

 gives a most interesting appendix on the question of disuse 

 and degeneration of wings in this ffy. Drosophila is a 

 good flier, but when bred for forty generations under 

 conditions that preclude the use of the wings, no 

 degeneration or diminution in these organs can be detected. 

 .'Mtogether this is a very laborious and careful piece of 

 research with bearings on many problems. 



(3) The next two papers deal chiefly with the ovarian 

 tissues of mammals. Much importance has been attributed 

 to Guthrie's experiments on the transplantation of hen's 

 eggs to foster-mothers of a different colour from that which 

 produced the egg. According to this writer, the offspring 

 of such foster-birds developed from the transplanted egg 

 and were influenced by the foster herself. Davenport has 

 recently denied both of these results, and now we have 

 a contribution by Prof. Castle and Mr. Phillips upon 

 similar experiments in guinea-pigs and rabbits. The 

 results arrived at are not a little confusing. In the 

 clearest case the procedure was as follows. The two 

 ovaries of an albino were removed at intervals of a week, 

 their places being taken by an ovary from each of two 

 black sows of differing ancestry. After recovery, the 

 albino foster-mother was put to an albino guinea-pig. 

 Two hundred days later two 9 9 were born, both of 

 which were black with red hairs, and two months later 

 one c? of the same colouring. Some three months after- 

 wards the albino died of pneumonia, and was found 

 pregnant with three full-grown c?c?. again black and with 

 red hairs interspersed. One of her daughters mated with 

 the same albino cT threw two albinos and one black. \ 

 control mating between a pure black 9 and the same 

 albino c? gave five young, all of which were black with 

 red hairs. 



These results are held to show that the pngrafted 

 ovarian tissue was the source of the black young pro- 

 duced by this cross albino X albino, and that no foster- 

 mother influence could be detected. But, on the other 

 hand, all the remaining cases £jo to show that, as in 

 Davenport's fowls, extirpation of the ovarv is not com- 

 plete, and is followed bv regenpration, the regenerated 

 ovary being the source from which the young produced 



