258 



NATURE 



[October 21, 1920 



reaction to environmental conditions. In the extreme 

 case the genetic machinery may, so to speak, be put 

 out of action ; genotypic potentiality no longer 

 becomes actual. We say that the character is not 

 inherited. We meet with such an example in Ranxw- 

 cuius aquatilis. According to Mer (Bull. Soc. Bet. de 

 France, i., 27, 1880), the terrestrial form of this plant 

 has no hairs on the ends of the leaf-segments, but 

 in the aquatic individual the segments end in needle- 

 shaped hairs— that is to say, hairs of a definite form 

 are produced in a definite' region. Again, Massart 

 (Bull. Jard. Bot. Bruxelles, i., 2, 1902) finds that in 

 Polygonum amphibium the shoot produces charac- 

 teristic multicellular hairs when exposed to the air, 

 but if submerged it ceases to form them on the new 

 growth. Every individual, however bred, behaves in 

 the same manner, and must therefore have the same 

 genetic constitution. In an atmospheric environment 

 genotypic expression is achieved ; in water it becomes 

 physiologically impossible. A limitation to genotypic 

 expression mav in like manner be brought about by 

 the internal environment, for the relation of the soma 

 to the germ elements may be looked upon in this 

 light. Thus in the case of a long-pollened and round- 

 pollened sweet pea, Bateson and Punnett (Report to 

 the Evolution Committee, Roy. Soc., ii., 1905) found 

 that the F, pollen-grains are all long, yet half of 

 them carry the factor for roundness. If we take the 

 chromosome view, and if it be presumed that the 

 factor for roundness is not segregated until the reduc- 

 tion division, the cytoplasm of the pollen mother-cells 

 mav be supposed to act as a foreign medium owing 

 to a mixture of qualities having been impressed upon 



it through the presence of the two opposite allelo- 

 morphs before the moment of segregation. We 

 should, consequently, infer that the round-pollen 

 shape is produced only when the round-factor-bearing 

 chromosome is surrounded by the cytoplasm of an 

 individual which does not contain the long factor. 

 If, further, we regard the result in this case as 

 indicative of the normal interrelation of nucleus and 

 cytoplasm in the hereditary process, we shall be led 

 to the view that, whatever the earlier condition of 

 mutual equilibrium or interchange between these two 

 essential cell constituents may be, an ultimate stage 

 is reached in which the rdle of determining agent 

 must be assigned to the nucleus. 



In conclusion, I would appeal for more organised 

 co-operation in the experimental study of genetics. 

 It is a not uncommon attitude to look upon the sub- 

 ject of genetics as a science apart. But the complex 

 nature of the problems confronting us requires that 

 the attacking force should be a composite one, repre- 

 senting all arms. Only the outworks of the fortress 

 can fall to the vanguard of breeders. Their part done, 

 they wait readv to hand over to the cytologists, with 

 whom it lies to consolidate the position and render 

 our foothold secure. This accomplished, the way is 

 cleared for the main assault To push this home we 

 urgently need reinforcements. It_ is to the physio- 

 logists and to the chemists that we look to crown 

 the victory. Bv their co-operation alone can we hope 

 to win inside the citadel and fathom the meaning of 

 those activities which take shape daily before our 

 eves as we stand without and observe, but the secret 

 of which is withheld from our gaze. 



The Air Conference, 1920. 



THIS Conference, consisting of representatives of 

 aviation in all its manv branches, lasted three 

 days, and was organised by the Air Ministry in order 

 to bring together persons interested in the subject in 

 conditions under which urgent problems could be freely 

 discussed with the knowledge that resolutions of the 

 conference arrived at after such discussion would be 

 welcomed by the Ministry as assisting the Secretary 

 for Air in his endeavour to promote in every way the 

 national interests depending on aeronautics. 



At the luncheon at which he presided on the first 

 ^ day of the conference, Mr. Churchill, Secretary of 

 State for War and Air, made this abundantly clear. 

 The future of military aviation, he pointed out, 

 depended on the widespread development of civil 

 aviation. "We," he continued — "I am speaking 

 for the Government — intend to Help civil aviation bv 

 every means in our power. You know our resources 

 are limited, but I hope the day is coming when it 

 will be possible for us to increase to some extent the 

 resources which are available for the development 

 of civil aviation. I do not think three years should 

 be too much to reconstruct the Air Service, so that 

 fathers of everv grade in our national life shall be 

 glad to send their sons into, it with the feeling that 

 they are giving them a good start in life, with the 

 possibility of a fine career." 



In the main (he added), civil aviation must flv by 

 itself, and the function of the Government would be 

 to facilitate its action — to liberate, stimulate, and en- 

 courage its action. The Air Estimates had shortly to 

 be considered. He excluded no solution which would 

 be likelv to help us through the two or three difficult 

 years ahead of us. No one could have the slightest 

 doubt about the ultimate future. To suppose that the 

 world, having got into the air, was ever going to 

 get out of it, was as absurd as to suopose that the 

 NO. 2660, VOL. 106] 



world, having taken to steamships, was going back 

 to schooners and sailing ships. They were gathered 

 there to drive away pessimism and to assert their view 

 that a great and bright future was opening for British 

 aviation. 



• The conference was held, by the courtesy of the 

 Lord Mayor, in the council chamber of the Guildhall 

 on October 12, 13, and 14, and the room was well 

 filled during all the sessions. The Lord Mayor him- 

 self welcomed the members, and in a few well-chosen 

 words expressed his sense of the importance of the 

 occasion. He then gave place to Lord Montagu of 

 Beaulieu, whose interest in aviation is known to all. 

 On the second day Lord Weir of Eastwood, Presi- 

 dent of the Air Council during a most critical part 

 of the war, presided ; while on the third day the 

 chairmen were, in the morning. Lord Beatty and, 

 in the afternoon. Lord Londonderry, Under-Secretary 

 of State for .Air, who had been detained in Ireland 

 and was unable, in consequence, to be present at the 

 opening sessions. 



The business details were admirably atranged. A 

 paper was read by some recognised authority on the 

 subject under discussion, one or two invited speakers 

 followed, and then the discussion w-as open to all 

 who cared to contribute. 



The conference was fortunate in that three out of 

 the six papers were read by the members of the .Air 

 Council responsible for the subjects considered, while 

 other members of the Council took part in the dis- 

 cussion. The audience thus learnt at first hand official 

 views on these matters. 



The conference was widely representative; invita- 

 tions had been sent not onlv to airmen, to designers 

 and builders of aircraft of all kinds, and to the repre: 

 sentatives of aeronautical organisations, but also to 

 the .Air .Attaches of foreign Powers, to members of 



