520 



NATURE 



[January 15, 1920 



cause a dilatation of capillaries if injected into the 

 circulation, but fail to do so in a perfused organ 

 unless both red-blood corpuscles and adrenaline are 

 ])resent in the perfusion solution. Large doses ot 

 histamine cause a condition like secondary shock. 

 The blood accumulates mainly in the capillaries, so 

 that, although the heart is beating vigorously, so 

 little blood passes through the veins to reach the 

 heart that the blood-pressure falls. Actual counting 

 of capillaries by Krogh shows that during rest only a 

 few capillaries contain blood. During activity many 

 more open up, so that the volume of blood that can 

 be accommodated in them is greatly increased. 



The discussion was continued by Prof. W. M. 

 Bayliss, Prof. E. H. Starling, Prof. A. D. Waller, 

 and Prof. N. Noel Paton. The trend of the discus- 

 sion was that the arterioles regulate the blood-supply 

 to the larger areas, and that variation in the size of 

 capillaries may allow more or less blood to accumulate 

 in them, thus affecting both the local and general 

 circulation. 



Three papers on accessory food substances were 

 read before the Section. Prof. W. D; Halliburton 

 contrasted butter and margarine. Margarine can be 

 made from various substances, but liquid oils must 

 be hardened. The hardening process destroys fat- 

 soluble vitamines, so that even if these are present 

 at the outset they are absent from the finished article. 

 Sophistication of food is dangerous because it may 

 remove accessory food substances. Children should 

 be given the butter and milk, as adults can better 

 withstand the absence of fat-soluble vitamines. 



Dr. E. M. Delf read a paper on the effect of heat 

 on the antiscorbutic food substance. Heating rapidlv 

 destroys antiscorbutic substance, but orange-juice 

 withstands heating better than most of the anti- 

 scorbutic substances. 



Miss A. J. Davey recorded the effect of preserva- 

 tives on the antiscorbutic substance. Lemon-juice is 

 a much more powerful antiscorbutic than lime-juice. 

 Lemon-juice was preserved by metabisulphite or by 

 its own rind-oil. The latter is more stable, and 

 retains its antiscorbutic effect for more than a \car 

 without much deterioration. 



Prof. h.. D. Waller demonstrated the decrease in 

 the electrical resistance of the hand that takes place 

 when a disturbance occurs in the central nervous 

 system. Coughing, burning, or even threatenin£< to 

 burn the opposite hand causes a decrease in elec- 

 trical resistance. Some peoole are more imaginative 

 and respond more to the threat than to the actual 

 stimulus, whilst others are more phlegmatic, and 

 give the greater response to the actual stimulus. 

 Prof. Waller also demonstrated the effect of walking, 

 running, and swimming on the output of carbon 

 dioxide. 



Dr. H. E. Roaf read a paper on the pathology 

 •of pellagra. Pellagra is due probably to the un- 

 suitable nature of the protein in the diet. The svmp- 

 toms point to an interference with the sympathetic 

 nervous system. No previous record is known of 

 distinctive pathological changes in pellagra. The 

 sympathetic nervous system showed marked plasmo- 

 lysis of its ganglion cells. It is possible that the 

 sympathetic nervous system may te affected bv diet 

 through the adrenal medulla. It is. however, neces- 

 sary to investigate the condition of the sympathetic 

 nervous system in other diseases. Dr. Roaf also 

 showed readings of climatic conditions made in Egypt 

 and in Palestine. Heat loss and the effect of cloth- 

 ing on heat loss were shown by readings made with 

 Prof. Leonard Hill's katathermometer. The protec- 

 tion by clothing from sun radiation was measured 

 hv sun-radiation thennometers. 



NO. 2^20, VOL. 104] 



BOTANY AT THE BRITISH ASSOCIATION. 

 T^H[E influence of the great war was distinctly to 



■•■ be noted in the character of the papers pre- 

 sented at the first post-war meeting. The Botanical 

 Section was fortunate in having a president so well 

 able to review the actual and potential plant resources 

 of our Empire, and to lay stress upon the pressing 

 necessity for their scientific development. This note 

 was struck again in the Forestry discussion, which 

 took place jointly with the Agricultural Section. To 

 this discussion Prof. A. Henry contributed a paper on 

 the afforestation of water-catchment areas. He urged 

 the planting of all suitable portions of gathering grounds 

 (which probably vary in different cases from lo per 

 cent, to 70 per cent.), largely on account of the para- 

 mount importance of insuring the purity of the water- 

 supply, which can so adequately and profitably be done 

 by this means. The scheme practicallv necessitates 

 co-operation between State and corporation for the 

 acquirement of the necessary land. 



What may be regarded as a real war paper was 

 furnished by Capt. H. Hamshavv Thomas, who gave 

 an account of the desert flora of Western Egypt some 

 twenty-five miles north-west of Cairo. The small 

 rainfall, coupled with hot days and dewv nights, con- 

 stitutes a set of conditions unfavourable to plant-life, 

 so that, unlike the sandy, rockv desert of Eastern 

 Egypt and Sinai, the Libyan Desert includes vast 

 stretches totally devoid of vegetation. The pruning 

 effect of the " khamseen " or sand-storms is very 

 marked, and reduces the plants to a dwarfed, tufted 

 ' habit. 



Other floral and ecological papers included the flora 

 of the district of the London Clay, by Mr. Horace W. 

 Moncton, and the northern invasions of New Zealand, 

 with special reference to Lord Howe Island, by Dr. 

 J. C. Willis. Mr. Moncton pointed out that the flora 

 of the London Clay in the Thames basin differs greatly 

 from that on contiguous areas of different geological 

 formation, and he illustrated his point from the sedges. 

 In addition to the twenty-eight species characterising 

 the London Clay, there are some twelve others 

 recorded, which, however, "do not seem to occur 

 where the London Clay forms the actual surface," 

 since "a covering of gravel or sand too slight to 

 mark on a geological map is sufficient to alter the 

 flora." 



Dr. Willis added to his well-known series of ob- 

 servations and conclusions concerning the origin of 

 floras data with regard to that of New Zealand and 

 Lord Howe Island, which led him to conclude that 

 the New Zealand flora includes a western invasion, 

 which probablv " followed the ridge upon which stands 

 Lord Howe Island." In consonance with his general 

 position. Dr. Willis put forward the view that the 

 endemics of Lord Howe Island are furnished by the 

 larger (older) families and genera. 



Considerable general as well as local interest w-is 

 raised in connection with Col. Godfrey's paper on the 

 orchids of Hants and Dorset, and the members of the 

 section were privileged to see on their expedition to 

 the New Forest one of the rare orchids mentioned. 

 viz. Malaxis paludosa. The author enumerated a sur- 

 prising number of natural hybrids occurring in the 

 district. 



As part of the joint discussion with the Zoological 

 Section in the field of Genetics, Mr. W. Brierley and 

 Dr. Ruggles Gates presented papers in which notable 

 contributions to our concepts of species and the trans- 

 mission of characters were put forward. Mr. Brierlev 

 treated of species in relation to his study of fungi, 

 and claimed that it is the inner physiological constitu- 

 tion rather than the chance morphological facies which 



