January 23, 19 13] 



NATURE 



The first of the two new contributions in this 

 volume is an interesting essay by Dr. Rudmose 

 Brown on the problems of Antarctic botany. He 

 agrees with Dr. Skottsberg in limiting the Ant- 

 arctic area to south of 60° S. He retains 

 Dougherty Island as existing, in spite of the 

 failure of the latest attempt to find it. Dr. Brown 

 refers to the striking poverty of the Antarctic 

 in land plants. In the South Orkneys (iat. 61° S.) 

 the expedition did not find a single flowering plant, 

 whereas in 79° N. in Spitsbergen some of the land 

 is carpeted with flowers of a hundred species. 

 Dr. Brown attributes the poverty of the Antarctic 

 flora to the mean temperature in the summer being 

 below freezing point and to the flocks of penguins, 

 which, in the absence of carnivorous animals, o\cr- 

 run the land. In his discussion of the origin of 

 the Antarctic land flora, Dr. Brown remarks that 

 the presence of an Arctic element in the mosses 

 might appear to support the doctrine of bipolarity, 

 which, he agrees with Dr. Skottsberg, has no 

 botanical support. That most of the zoological 

 evidence is also opposed to the theory is remarked 

 by Mr. F. Jeffrey Bell in his interesting intro- 

 duction to the last volume on the collections of the 

 National Antarctic Expedition. Mr. Rudmose 

 Brown explains the presence of the Arctic mosses 

 by their transmission by sea birds, of which some 

 species range almost from pole to pole. Some 

 plants may have been introduced to Antarctica by 

 wind; for Dr. Fritsch found in material from the 

 South Orkneys the pollen of Podocarpus, which 

 must have been blown from South America. Dr. 

 Brown regards the whole Antarctic land flora as 

 derived from South America, a conclusion which 

 is supported by the absence of New Zealand plants 

 from eastern Antarctica. 



The second new memoir is by Dr. J. H. Harvey 

 Pirie on Antarctic bacteriology. Levin has shown 

 that many Arctic birds and seals are free from 

 bacteria. Dr. Pirie, however, found that three out 

 of the four species of seals examined and ten of 

 the fifteen species of birds contained bacteria. 

 His general results agree with those of Gazert, 

 Ekelof and Charcot of the German, Swedish and 

 French expeditions respectively, that Antarctic 

 animals usually contain bacteria but may be sterile. 

 Dr. Pirie found that the air, when carefully col- 

 lected from the crow's-nest and the deep sea 

 samples, was always sterile. In seven out of ten 

 cases the surface water of the sea yielded bac- 

 teria. Denitrifving bacteria are, however, very 

 scarce, and Dr. Pirie points out that the nitrogen 

 so continuously added to the sea is eliminated by 

 the action of these bacteria. Owing to the slight 

 bacterial denitrification in the polar seas, plant 

 and animal life is more abundant there than in 

 the tropics. 



Hence is explained the extraordinary abundance 

 of individuals in the polar seas in spite of the 

 relative povertv in species, a fact which is referred 

 to by Mr. Jeffrey Bell in the new volume of the 

 reports on the collections of the National Ant- 

 arctic Expedition. He quotes Mr. Hodgson's 

 NO. 2256, VOL. 90] 



I remark that it was usual to take from ten to thirty 

 I thousand amphipods at a single haul, and Mr. 

 j Bell estimates that the collection included nearly 

 j ten thousand specimens of one schizopod. Mr. 

 Bell refers to the two new species of Cephalodiscus 

 and Mr. Hodgson's rediscovery of the ten-legged 

 Pycnogonid as perhaps the most interesting of 

 the biological results of the expedition. The 

 volume includes three memoirs, a report on some 

 young holothurians by Prof. MacBride, in which 

 he suggests that these animals were derived from 

 primitive echinoids, a hypothesis which appears 

 less probable since Walcott's discovery of a 

 Cambrian holothurian, which is much more ancient 

 than any known echinoid. The second memoir is 

 by Prof. Ehlers on the polychaets, and the last is 

 by Prof. Fritsch on the freshwater algse. This 

 memoir is perhaps of less interest than the same 

 author's report on the algae collected by the Scotia, 

 for Messrs \V. and G. S. ^Vest have previously 

 described the collection from South Victoria Land 

 brought back by the Shackleton expedition. In 

 the South Orkneys, in addition to the red snow 

 which is familiar in Polar and Alpine regions, there 

 is a yellow snow, due to a mixture of eight'jen 

 species of algae and two of fungi. The colour is 

 due to the numerous globules of fat. The general 

 affinities of this flora are planktonic, and Dr. 

 Fritsch suggested that it was carried ashore by 

 the wind. 



The last part of the volume on the geographical 

 and geological results of the German south polar 

 expedition contains a posthumous memoir by E. 

 Philippi, the geologist of the expedition, on the 

 intra-glacial material found near the winter 

 quarters of the Gauss. The icebergs examined 

 came from the east, and contained fragments of 

 granite, gabbro, gneiss, crystalline schists, and 

 a red quartzite, but no fossiliferous rock or repre- 

 sentative of the "3'oung- volcanic" series. Ice- 

 bergs were also examined eight miles west of the 

 Gaussberg, and they contained similar rocks. 

 Philippi concludes from the characters of the ice 

 that it must have flowed over an irregular un- 

 dulating land. The erratics collected by the expedi- 

 tion have been identified by Dr. Reinisch and in- 

 i elude a similar but more varied series of rocks. 

 They include granite and aplite, gabbro and gabbro 

 porphyrite, many varieties of gneisses and horn- 

 blende schists, some of which are rich in pyrites, 

 marble, quartzite, calc-silicate rock and sandstone. 

 There is no true mica schist or phyllite. This 

 association of rocks supports the view that western 

 Wilkes Land is geologically a southern continua- 

 tion of Western .Australia. The third memoir in 

 this part is a valuable study by Reinisch of the 

 rocks collected in various Atlantic islands from 

 the .Azores to St. Helena. His report and anal3'ses 

 confirm the conclusion that the volcanic rocks of 

 these islands mainlv belong to the alkaline series, 

 though, as Reinisch remarks, some of the 

 basaltic rocks are intimately related to augite 

 andesites. 



J. W. G. 



