688 



NA JURE 



[November io, 1923 



of chromosomes present in the somatic cells. In the 



l„tf •• division he found one pair of bivalents 



„, r than the others, but the individual 



„H...:.. I iliis |);iir weft- of ccjual sizc ; thus no 

 signs of th. 'C possibiUty of two 



tym«s of nil' . ' 



I have cxanuiicd its clot»e ally, Lychnis alba. Mill., 

 and find similarly twenty-four somatic chromosomes. 

 of which two are larger than the rest. In the female 

 plant at the reduction division these two appear 

 similar; thus the daughter nuclei are alike. In the 

 male, however, the two large chromosomes differ from 

 one another both in size and shape ; the larger one is 



bent, somewhat in the 

 shape of a hockey stick. 

 *,i\\\ ///1\^ w'^" *^^ curved end 



f/l\V\ dli^M pointing outwards from 



T^^ the spmdle, whilst the 

 ^mjjk smaller somewhat pear- 

 ^\\\l I//V shaped one is not more 

 y// than two-thirds its size 

 „ „ . A- ■■ ■ r L ■ {Vie. 1). The shape is 



Fig. I.— Helerotype diviwon in Lydtnts ^ P ' ^ . J , . 



ttlha. Mill. A : male ; 11 : female. quite constant and the 



appearance is the more 

 striking in that this pair of chromosomes takes the 

 stain muc"h more strongly than the others. 



Since L. alba is so closely related to /-. dioica, in 

 which ShuU has demonstrated sex-linked characters 

 with the male heterozygous for sex, it seems more 

 than probable that we have here a definite case of 

 an XY pair of chromosomes in the male with a corre- 

 sponding XX in the female. This is the first definite 

 record of sex chromosomes in a Dicotyledon. 



A full account of this and other species of Lychnis 

 and their hybrids will be published shortly. 



Kathleen Bever Blackburn. 



Botanical Department, Armstrong College, 

 Newcastle-upon-Tyne. 



Powers of Perception of Birds. 



My attention has been directed to a note in Nature 

 of November 18, 1922 (vol. no, p. 677), containing 

 references to an article on " The Sense of Smell in 

 Birds " (Nature, June 17, 1922, p. 783), and to Dr. 

 H. H. Beck's paper on " The Occult Senses in Birds " 

 {A uk, 1 920, xxxvii. 55) . As your note intimates, there 

 is evidence that neither by " occult sense " nor by 

 smell do turkey vultures find their food. They cer- 

 tainly depend largely upon a very keen sense of sight, 

 as is shown by the following incident. 



A toy rabbit consisting of white plush and excelsior 

 packing was given to our little girl a number of years 

 ago. It proved to be a favourite toy. One night 

 she forgot it and left it lying in the yard. As we sat 

 at breakfast the next morning we were greatly sur- 

 prised to see a turkey vulture strutting in a circle 

 about the toy rabbit as it lay on the ground, and 

 eyeing it with head turned to one side. Here was 

 something new to his experience. It was certainly 

 the form, but not the substance of a dead rabbit. 

 If the turkey vulture has an " occult sense," in this 

 case at least he did not depend upon it, or, doing so, 

 was completely deceived. 



The position of the writer of the note in Nature 

 is one to which we can subscribe when he says : "It 

 is surely more reasonable to attribute these [powers 

 of perception] to greater acuteness of the known 

 senses than to imagine new senses for which no 

 physiological basis can be suggested." 



Chas. W. Palmer. 



Northeast High School, Philadelphia, Pa., 

 October 15. 



NO. 2819, VOL. I 12] 



Population and Unemployment. 



In the r^umd in Nature of Octol>er 13 of t 

 presidential address by Sir William li«*vf'ridR** to 1 : 

 kconomics Section of the 

 point which raised so much 

 mdicated by this sentence: inc: 

 trol is not required by anything in 

 Europe before the War, and is ir 

 present troubles." As this idea h 

 nailed by many, may I ••-••>• out tii.n .-^i ..iiii,i..i 

 entirely ignored the 10 !es. Those who are 



unemployable throni'i' ■ ...v,. f... 1,1,. .,.,t.,i,..i 



ness, general debilit 



of a " C 3 " and \u.. .^ 



do not appear in the ordinary list 

 but they are. nevertheless, a huge fin.' 

 the community. Both a financial strain and :i 

 physiological danger to the race, they not onlv brof 1 

 and reproduce their like if left without birth ( ■ 

 but they are brought into existence in otJ. 

 healthy stocks whenever mothers under hard c*-; 

 ditions reproduce too rapidly. Only by means ' : 

 constructive birth control can women space their 

 children so as to ensure the likelihood of reasonable 

 health to those they bear under the modem aixl 

 unnaturally hard conditions of slum life. 



While Sir William Beveridge may play at ninepin> 

 with the primitive " Malthusian theory," it is most 

 dangerous that, misled by his phrases, uncritical 

 persons who confuse Malthusianism with constructive 

 physiological birth control should be given such 

 inopportune encouragement. Statistics confirm our 

 common-sense observation that intelligent members 

 of the better stocks are widely using birth control ; 

 hence, unless we do have an increase of birth control 

 .so that the inferior stocks also use it, we shall con- 

 tinue racially to deteriorate at an ever-accelerating 

 speed. Marie C. Stopes. 



President of the Society for Constructi\ c 

 Birth Control and Racial Progress. 



7 John Street, Adelphi, 

 London, \V.C.2. 



A Possible Cure for Cancer. 



Whilst reading Prof. Johnstone's remarks (Lanes. 

 Sea-Fish. Lab. Report for 1922 (1923), p. 19) on 

 malignant (cancerous) growths in fishes, I was struck 

 by and seized upon the statement that " wen " is an 

 example of a controlled growth. 



So long ago as 1908 I remember Prof. Farmer 

 suggesting in his lectures on " The Cell " that 

 " cancer " might be due to lack of control of the 

 individual as a whole over certain tissues, and this 

 view has gained force ever since that time ; but now 

 arrives a statement that " wen " is a controlled 

 growth. Let it be assumed that both statements 

 are correct ; then the individual with a wen contains 

 or has contained in its system somewhere a control- 

 ling influence which — from many analogies — may 

 not improbably exist in the blood. Now if wens 

 occur in other suitable animals than man it would 

 be an easy matter to extract plasma or other com- 

 ponents of the blood for injection into other in- 

 dividuals of the same species having uncontrolled 

 (cancerous) growths in order to test whether the 

 controlling influence exists there and can be passed 

 on to another individual. 



If the suspicion were confirmed, a cure for cancer 

 would be obtained, as the application of a similar 

 process to man would no doubt follow ver>' swiftly. 



Or again, assuming that individuals with wens 

 have an obvious control of a tendency to cancerous 



