656 



NATURE 



[February 13, 191 3 



<vol. vi., part 5) contain a portrait and memoir of 

 tlie late Dr. William Watson, Indian Medical Ser- 

 vice, who was president of the society from 1888 to 

 iSi)!, and died on June 16, 1912, at the age of eighty. 

 Dr. Watson was stationed for many 3-ears at Naini 

 Tal, where he saw the disastrous landslip of 18S0, 

 acquired special knowledge of' Indian botany, and in 

 187^ was commissioned by Government to furnish a 

 report on the flora of Kumaon. 



The London County Council has issued a handbook 

 to the special series of cases in the Horniman Museuin 

 illustrating animal locomotion. The exliibit appears 

 to be of considerable extent, displaying adaptations 

 to swimming, creeping, burrowing, running, leaping, 

 climbing, "parachuting," and flying in various classes 

 of animals, these adaptations being explained in the 

 handbook, which has been compiled by Mr. H. N. 

 Milligan, under the supervision of Dr. Haddon. A plate 

 illustrates the convergence of type presented by vari- 

 ous groups of swimming vertebrates, as exemplified 

 by fishes, ichthyosaurs, cetaceans, and sirenians. We 

 believe a special exhibition illustrative of flying is 

 shortly to be opened in the Natural History Museum. 



Under the title, " Die Mutationen in der Erblich- 

 keitlehre," a lecture delivered by Prof. Hugo de Vries 

 in October, 1912, at the inauguration of the Rice 

 University, Texas, the largest scientific institution in 

 the southern States, for the building and equipment 

 of which the founder, Mr. W. M. Rice, bequeathed 

 ten millions of dollars, has now been published (Ber- 

 lin : Borntraeger). In this lecture Prof, de Vries 

 reviews the relations between his well-known mutation 

 theory and other theories of evolution — natural selec- 

 tion, orthogenesis, and neo-Lamarckism — replies to 

 various criticisms of the mutation theory, and sum- 

 marises the chief advances made during recent years 

 in the study of mutation, including the important 

 cytological results obtained by Gates and other investi- 

 gators. This brochure, presenting the author's latest 

 views, and recounting the progress made during tlie 

 ten years that have elapsed since the publication of 

 his " Mutationstheorie," will be useful to students of 

 evolutionary biology ; numerous references to the 

 recent literature of the subject are included within 

 the comparatively small compass of forty-two pages. 



The Cambridge University Press has published 

 Prof. J. Ward's Henry Sidgwick memorial lecture for 

 igi2, "Heredity and Memory" (is. 6d. net). The 

 lecture deals in an interesting manner with the hypo- 

 thesis that heredity is a form of memory. The author 

 differs from some who accept Semon's mnemic hypo- 

 thesis in believing that it is useless to seek a physical 

 e.xplanation of "engrams," for memory is essentially 

 a psychical process, and heredity, being fundamentally 

 racial experience, is also psychical rather than physical. 

 The general position adopted is thus frankly vitalistic 

 or animistic, and this is justified on the ground that 

 since we know psychical phenomena (mind and pur- 

 pose) in ourselves, the principle of continuity demands 

 that they must exist also in the lower organisms. 

 It is not justifiable to ascribe the vital phenomena of 

 the lowest organisms to purely phvsical causes when 

 .>^0. 2259, VOL. 90] 



we have no conception of how such causes could 

 produce the mental phenomena which are character- 

 istic of the highest. A considerable portion of the 

 lecture is devoted to a criticism of W'eismann, but a 

 good deal of recent work, some of which might have 

 been used in support of the author's thesis, and some 

 which tells against it, is not mentioned. 



Mr. R. L. Ditmars, the curator of reptiles of the 

 New York Zoological Society, contributes to a recent 

 number of Zoologica (published November, 1912) an 

 interesting paper upon the feeding habits of snakes, 

 based in the main upon observations of specimens 

 in captivity. For the purpose of systematising his 

 subject-matter, the author divides these reptiles accord- 

 ing to their metliod of taking food into two main 

 groups, the non-venomous and the venomous. The 

 non-venomous group contains : (a) constricting species, 

 like the Boidas and some Colubridae, which coil round 

 their prey and squeeze it to deatli ; (b) semi-constric- 

 tors, like the Colubrine genera Zamenis and Spilotes, 

 which overcome their prey by holding it in a single 

 coil or by pressing it to the ground, and swallow it 

 alive; (c) non-constricting species, like the Colubrine 

 genera Tropidonotus and Heterodon, and the insec- 

 tivorous Typhlopidae and Glauconiidje. The venomous 

 group contains : (a) the poisonous ColubridK, like the 

 sea-snalces (Hydrophis) and the cobras (Naia), which 

 seize their prey and hold it until dead, when swallow- 

 ing begins ; (h) the vipers, which stab their prey and 

 immediately release it, awaiting its rapid death by 

 poisoning before attempting to swallow it. This 

 classification is not claimed to be in any sense abso- 

 lute, but is adopted to indicate the principal methods 

 of overcoming prey practised by snakes. Some very 

 interesting observations are recorded, especially those 

 relating to an example of the king cobra, or Hama- 

 drj-ad {Naia bungarus), an example of which showed 

 by its behaviour that it knew the difference between 

 a water viper (Ancistrodon piscivorus), a poisonous 

 Crotaline, and a harmless water snake {Tropidouolus 

 taxispiloiis), although to the human observer the two 

 matched one another closely. The viper it refused to 

 touch, but the innocuous specimen it seized at once. 

 This experiment gains in interest from the fact that 

 the two species offered for food to the cobra are 

 foreign to its native country. 



Although the study of plant geography dates back 

 at least as far as Humboldt's time, plant ecology, 

 which is concerned with the detailed and systematic 

 study of plant communities — the groupings of plants 

 found associated together under definite conditions of 

 life — is one of the youngest branches of botany. One 

 of the requirements of a young but progressive sub- 

 ject is a suitable nomenclature, and this Dr. H. 

 Brockmann-Jerosch and Dr. K. Riibel have attempted 

 to supply in their recently published work, "Die Ein- 

 teilung der Pflanzcngesellschaften " (Engelmann, 

 Leipzig, price 2.50 marks). They divide plant com- 

 munities into four main types — " Lignosa " (woodland 

 and scrub), " Prata " (meadow and marsh), 

 " Deserta," and " Phytoplankton." Each of these is 

 divided into a number of classes of formations, and 

 these again into groups of formations, and these are 



