F"ebruary 24, 1 9 10] 



NATURE 



497 



Apropos of the article on colour-blindness in Nature of 

 January 27, Mr. C. R. Gibson has forwarded us a reprint 

 on " An Occasional Peculiarity hi My Own Colour Vision " 

 (Royal Philosophical Society of Glasgow, iqo8). On three 

 occasions he has failed to distinguish brilliant red objects 

 or light until the colour has been accidentally brought to 

 his notice, when the colour appears immediately to flash 

 into his consciousness, and he experiences a feeling of 

 amazement that he could have been oblivious to it. There 

 is every reason to believe that, as a rule, his colour vision 

 is normal. If this is the case, we must conclude that 

 there is a temporary block in the transmission of the 

 nervous impulses from the periphery to the cortex of the 

 brain, and that the position of the block is in the higher 

 cerebral portion of the visual path. Bordley and Gushing 

 have recently brought forward evidence of alterations in 

 the field of vision for colours in cases of increased intra- 

 cranial pressure due to cerebral tumours. The existence 

 of a special cortical " centre " for the perception of colours 

 is the subject of dispute. That there must be cortical re- 

 presentation of the impulses engendering colour perception 

 is a point which need not be laboured. The problem is 

 rather that of the dissociation, or the nature of the associa- 

 tion, of the mechanism of colour perception with that of 

 light and form perception in the higher levels of the brain. 

 Evidence such as tlfat brought to our notice by Mr. Gibson 

 helps to elucidate this problem, though more definite 

 evidence is obtained from cases such as one admirably re- 

 ported by Dr. Edwin Bramwell in the Review of Neurology 

 and Psychiatry for this month (vol. viii., February). Here 

 a cerebral abscess secondary to bronchiectasis involved the 

 cortex of the occipital lobe, and was accompanied by fits 

 with a visual aura and by hemi-achromatopsia. 



The production of rhizoid-like processes from cells of 

 Spirogyra filaments when growing under unnatural con- 

 ditions has been recorded by several observers from 

 De Bary onwards. Evidence has tended towards the con- 

 clusion that these are malformations, and this opinion 

 receives confirmation in a paper, by Dr. Z. Woycicki, 

 which appears in the Bulletin International de I'Acadimie 

 des Sciences, Cracow (October, 1909). In this case the ill 

 effects are attributed to the gaseous atmosphere in the 

 laboratory. A similar formation of rhizoids was induced 

 in cultures of Mougeotia genuflexa, while the injection of 

 gas into cultures of Cladophora fracta produced a crop of 

 resting spores. 



It is a debated point whether modifications in plants 

 induced by special physiological conditions can be inherited 

 or not, and a number of experimental investigations, chiefly 

 with lower organisms, have been made with varying 

 results. An account of experiments with Aspergillus niger, 

 carried out by Mr. K. Kominami, is published as vol. 

 xxvii., art. 5, of the Journal of the College of Science, 

 Tokyo University. The fungus was grown for several 

 generations in a strong (6 per cent.) solution of common 

 salt, and the cultures so obtained were compared with the 

 cultures raised in normal media. With regard to germina- 

 tion, the conidia of the modified stock started more rapidly 

 and strongly than those from the normal plants, and this 

 superiority was maintained throughout ten generations. 

 On the contrary', modifications of the organism produced 

 in poisonous solutions did not appear to be transmitted 

 to succeeding generations. 



In connection with a variety of plants which have been 



found to irritate the skin when handled by gardeners and 



others, Mr. J. H. Maiden, Government botanist for New 



South Wales, has commenced to collect and summarise 



NO. 2104, VOL. 82] 



evidence of authentic cases. In the Agricultural Gazette 

 of New South Wales (December 2, 1909) Mr. Maiden deals 

 with a number of plants — Oenothera biennis, L., Hedera 

 helix, L., various Primulas, Hyacinthus orientalis, L., 

 and varieties, Thuja Douglasii, Agave americana, and 

 others — quoting specific instances of the irritation caused. 

 He states that he has found literature relating to plants 

 which irritate the skin — other than Rhus and Primula, 

 which he dealt with in an earlier issue of the gazette re- 

 ferred to — exceedingly scarce or even wanting. Mr. 

 Maiden would be glad of references or authoritative state- 

 ments as to irritation or " poisoning " caused by any wild 

 or cultivated plants. 



In the Bulletin International de VAcadimie des Sciences 

 de Cracovie for November, 1909, appears a paper on the 

 mineral alstonite, by Dr. Stefan Kreutz, in which he dis- 

 cusses the vexed question whether this substance is a 

 double salt or an isomorphous mixture of the three 

 members of the group, aragonite, witherite, and stron- 

 tianite. From a careful consideration of his own and 

 earlier observations he concludes that the second view is 

 probably correct, but acknowledges some as yet inexplic- 

 able discrepancies. He explains the complex twinning 

 either as simultaneous twinning about both |iio[ and 

 ]i30f or as repeated twinning about {no',, as in the case 

 of alexandrite. 



Prof. A. Woeikop contributes an extremely interesting 

 and suggestive study of the sources of human food-supply 

 to La Giographie (vol. xx., Nos. 4 and 5, pp. 225 and 2S1). 

 After pointing out that the substitution of any manufac- 

 tured substance for vegetable food is extremely improbable, 

 inasmuch as plant life is capable of storing solar energy 

 in a much more economical manner than any machine, the 

 author emphasises the facts that scarcely any one kind 

 of food is universally regarded as a necessary of life, while 

 many kinds which are now regarded as necessaries by 

 certain peoples were almost unknown to them a few 

 generations ago. From an examination of the geographical 

 and economic conditions. Prof. Woeikof concludes that 

 meat will in the future become so expensive as to be prac- 

 tically unavailable as an ordinary food, and that the supply 

 must sooner or later be drawn wholly from the vegetable 

 kingdom. He is of opinion that the application of scientific 

 methods will increase the productiveness of the agricultural 

 land of the world to an almost unlimited extent. 



In the Atti dei Lincei (xix., i). Dr. Umberto gives a 

 short note on the solution of the hydrodynamical equations 

 for two-dimensional steady motion in a region bounded by 

 free stream lines, the remaining spaces being occupied by 

 fluid at rest. 



Under the title of " L'Energie," a French translation 

 of Prof. Ostwald's classical work has been added to the 

 new scientific series published by M. F^lix Alcan, Paris, 

 under the editorship of Prof. Borei. The translator is 

 M. E. Philippi, and the price is 3.50 francs. 



From the Annual Register we learn that the American 

 Mathematical Society now consists of 618 members, as 

 against 601 at the beginning of last year. The library 

 now contains nearly 3300 volumes, as against between one 

 and two hundred nine years ago. The books can be 

 borrowed through the post by members, and one of the 

 aims of the library is to preserve as complete a record as 

 possible of the growth of mathematics in America. 



The Revue ginerale des Sciences (xx., 23) contains a 

 second article, by Prof. Fr^ddric Houssay, on the form 

 and stability of fishes. The author has now made models 



