December i6, 1909] 



A^A TURE 



zoi 



Germany, especially in comparison with applied chemistry 

 and its followers. 



H. Fischer, the discoverer of the symbiosis of N-bacteria 

 with microscopic soil algse, in a valuable article on soil 

 bacteriology, summarising and discussing the results 

 already obtained, urges the necessity of treating the subject 

 as a botanical one and of encouraging botanists to devote 

 themselves to it if advances commensurate with its prac- 

 tical importance are to be made. Thus at present there 

 is, he states, no known method of bacteriological soil 

 investigation which satisfies the requirements of science 

 and practice. Exclusive of the discovery of the N-fixing 

 power of the bacteria of leguminose roots, little of prac- 

 tical value has so far been ascertained. Azotobacter 

 chroococcum is, in passing, quoted as a calcicole plant, 

 thus serving, like some flowering plants, as a soil 

 indicator. 



Wieler writes on the smoke nuisance as it affects plant 

 life. He shows how little the subject is understood, urges 

 the creation of a smoke institute for the investigation of 

 smoke problems, and the employment in legal cases of 

 smoke experts as judicial arbitrators. Wieler reviews 

 critically the publications of recent years on smoke, and 

 deals especially with the sulphur compounds on which he 

 has himself worked. The prevention of damage to plant 

 life by smoke is a botanical subject. 



P. Sonntag describes the results of his examinations of 

 the ductility and breaking point of the bast fibres of some 

 half-dozen different palms, corrects earlier observations on 

 the subject, and shows the practical bearing of the ques- 

 tion, e.g., on the selection of fibres for street sweepers. 



Count Arnim, well known for his devotion to the pro- 

 duction of new varieties of cereals, contributes a stimu- 

 lating cu'ticle on the production of new varieties of 

 potatoes. He contends that hitherto the method pursued 

 has been empirical, the object having been to meet the 

 speculative trade demand for new varieties each year. 

 Scientific men are invited to answer certain questions 

 pressing for solution, and to aid the conscientious prac- 

 tical man in the search for trustworthy starch-producing 

 disease-resisting varieties. Results hitherto obtained in 

 potato-culture experiments are of necessity contradictory, 

 not being based on scientific principles. 



L. Bernegau deals with the utilisation of dried potato 

 tubers and of the sweet-potato (batatas) in the German 

 colonies of West Africa. The article is of value to all 

 interested in the industrial application of colonial economic 

 products. Other articles by Bernegau deal with the Togo 

 lemon (Citni.<: medico) and with Cola acuminata and 

 C 7<era seeds. 



One of the most important papers in the volume is 

 that by F. Muth on the influence of the nature of the seed- 

 bed on the germination of seeds. Contrary to the opinion 

 prevailing in Germany that, though the nature of the 

 seed-bed is of minor importance, strong filter or blotting 

 paper is the best medium, Muth finds, as a result of 

 many trials of every kind of seed, that blotting paper for 

 most seeds does not provide the best seed-bed. He re- 

 commends unglazed white or yellow porcelain dishes. 

 The results of the seed-testing in the Government station 

 in Ireland, of which I have charge (more than 2000 tests 

 being made annually), fully support Muth. Further, we 

 find that for cereals a soil-test, apparently not tried by 

 Muth. gives better results than the porcelain dishes. Brick 

 supplies an illustrated account of the diseases of cocoa, 

 rubber, and other tropical plants of cultivation, and Appel 

 a, now somewhat belated, paper on potato leaf-roll. 



The report is one which no one concerned with economic 

 botany should overlook, and reveals the many-sided prac- 

 tical bearings of botany. T. J. 



A NEW METHOD IN ANIMAL PSYCHOLOGY. 

 'T'HOSE who remember the Huxley lecture delivered in 

 igo6 by Prof. Pawlow, in which he complained that 

 the physiology of the sense organs had hitherto suffered 

 from the evil influences of psychology, will turn with 

 interest to a paper entitled " The Method of Pawlow in 

 .\nimal Psychology," which is contributed to the August 

 number of the Psychological Bulletin by Messrs. R. M. 

 Vcrkes and S. Morgulis. The method which Prof. Pawlow 



NO. 2094, ^'OL. 82] 



introduced consists in studying the modifications of the 

 salivary reflex under various mental conditions. By a 

 simple operation a salivary fistula is formed on the outer 

 surface of the cheek of a healthy dog ; the wound quickly 

 heals, and the animal suffers no further inconvenience. 

 The flow of saliva under different conditions is studied by 

 collecting it from the fistula and observing its volume and 

 viscidity in given intervals of time. Pawlow calls the 

 salivary reflex " unconditioned " when (as, for instance, 

 on the introduction of food into the mouth) the stimulus 

 naturally and directly calls forth the reflex. On the other 

 hand, a " conditioned " reflex occurs through artificial and 

 indirect causes. Thus, if a sound of constant pitch is 

 produced near the dog on every occasion when food is 

 given, this particular sound (after adequate practice) is 

 sufficient to cause a secretion of saliva in the absence of 

 food. According to Nicolai, the " reflex " thus obtained 

 is a complicated process, the secretion being connected 

 only indirectly with the sound-stimulus by the mediation 

 of the "idea of eating." When once such a conditioned 

 " reflex " has been established, the interest of the experi- 

 ment consists in seeing to what extent, if at all, the 

 " reflex " is evoked by modifying the stimulus, _ e.g. by 

 varying its pitch, timbre, or loudness, or by including 

 the tone in a chord. 



The paper gives a lengthy resume of the study of 

 auditory reactions made in this way by Selionyi, one of 

 Pawlow 's pupils. .\ paper by Orbeli, another of his 

 pupils, also written in Russian, is likewise abstracted in 

 considerable detail. This deals with the visual reactions 

 of the dog. The writer concludes that the " study of 

 conditioned salivary reflexes furnishes no indication that 

 rays of light of different wave-length are received as 

 distinct stimuli by the eye of the dog," although such 

 reflexes " are essentially dependent upon the intensity of 

 the light-stimulus." N'i'colai likewise fails to find evidence 

 of colour-vision in the dog. It would, however, be rash 

 to conclude from these experiments that dogs are colour- 

 blind. The dogs mostly used in Pawlow's laboratory 

 were a mixed breed of hunting dogs, and it may well be 

 that in this particular breed colour-differences are very 

 ill attended to. Moreover, it is quite conceivable that 

 when an animal has been trained to salivate, say, to a 

 blue stimulus, a yellow stimulus may also cause salivation, 

 and vet mav be clearlv distinguished in the dog's conscious- 

 ness'from the blue, this shows the weakness of Pawlow's 

 method and the cautions which are necessary in deducing 

 the mental states of an animal from the study of its salivary 

 secretion. To judge from the list of forty-two papers pub- 

 lished (mostlv in Russian) by Pawlow and his pupils since 

 1004, the .St. Petersburg school of physiologists has un- 

 bounded faith in the possibilities of the method. 



T 



THE MESSINA EARTHQUAKE. 

 HE Messina earthquake of December, 1908, will prob- 

 ably occupy the attention of Italian seismologists for 

 some time to come. In the meantime. Dr. Mario Baratta 

 has published a summary of the results at which he has 

 arrived during an investigation made under the auspices 

 of the Italian Geographical Society. The great shock, he 

 remarks, was not announced by any slight movements m 

 the district chiefly affected. The greater part of this dis- 

 trict lies in the Calabrian peninsula, bounded by a hne 

 which just includes Palmi, San Procopio, San Stefano, and 

 Pellaro. In Sicily the bounding line includes Faro 

 Superiore, close to the north-eastern corner, and passes a 

 short distance to the west and south of Messina; but, 

 even in this region of maximum devastation, there are 

 small areas within which the buildings appear to have 

 been miraculously preserved. 



Excluding Reggio and Messina, where the number of 

 victims is still unknown, the mortality reached a maximum 

 at Cannitello, with a percentage of a-.- : in a few places 

 it ranges from 20 per cent, to 30 per cent., more frequently 

 it lies between 10 per cent, and 20 per cent., while in 

 most places it was less than 10 per cent. Besides the 

 principal meizoseismal area, there are other regions 

 marked by an increase of intensity, such as the well- 

 known zones of Monteleone, La Plana, Ferruzzano, &c., 

 so strongly disturbed in 190-;, 1783, and 1907 respectively. 



