I04 



NATURE 



[April ii, 191 8 



or bacteria, we need more diagnostic data, for the 

 method of combating the disease must necessaril)' 

 depend on the nature of the micro-organism to be 

 combated. David Ellis. 



J^oyal Technical College, Glasgow, March 30. 



The object of the article on bee disease which 

 appeared in N.^ture of March 21 was to emphasise 

 the fact that, though bees suffer from many diseases, 

 the macroscopic symptoms" are practically the same, 

 and to claim that the only acceptable definition of 

 "Isle of Wight disease" is the "disease caused by 

 Nosenia apis." As Mr. Ellis's experience would ap- 

 pear to support this contention, it is to be regretted 

 that he should have received the impression that 

 Nosema, when found, has no causal connection with 

 the disease. The correct deduction would appear to 

 be that, in spite of the guarantee of the professional 

 lecturer on bee-keeping, the bees he examined were 

 not suffering from " Isle of Wight disease." It would 

 at any rate be interesting to know on what scientific 

 data this guarantee was given. The conclusions in 

 the last sentence of Mr. Ellis's communication are 

 identical with those drawn in my article. 



The Writer of the Article. 



Prices of Scientific Apparatus. 



The. method of advertising at present adopted by 

 some of our scientific instrument makers is, I venture 

 to think, open to serious objection. The prices men- 

 tioned are, it would appear, not the current prices at 

 all. An addendum (printed in small type or in some 

 other inconspicuous way), informs the public that, 

 owing to the war, the prices quoted in the advertise- 

 me/it are subject to an addition of 10 or 20 per cent., 

 and in some cases to as much as 33 per cent. Would 

 it not be advisable to abandon entirely the publication 

 of pre-war prices, and to quote instead the sums for 

 which the various forms of apparatus are to be ob- 

 tained at the time the" advertisement meets the public 

 eye? Fredk. J. Brodie. 



Loxley Road, Wandsworth Common, S.W., 

 April 2. 



COTTON-GROWING STATISTICS. 

 'X'HE forecasting- of the cotton crop, upon 

 -*- which depends one of the greatest industries 

 of the world and in which Great Britain is especi- 

 ally interested, has settled into a mixture of reports 

 based on a g-lance round a cotton field, a chat with 

 a proprietor, and a combination of a few climatic 

 notes which a Government department wisely 

 issues for a farmer's g-uidance. It is all unsubstan- 

 tial, but these reports are spread over the world 

 and are used as a basis for business and specula- 

 tion according- to the credit any particular reporter 

 may have at the moment. 



It is not surprising- that serious attempts are 

 made to eliminate this casual method and estab- 

 lish a scientific basis in its stead. A short time 

 ago a particular investigation conducted in Egypt 

 necessitated the obtaining of a certain amount of 

 data of the growth of the cotton plant. The collec- 

 tion of the data was carried out on scientific lines , 

 and evidently serv.ed its purpose. It was found, ! 

 however, that the data and method used for this 

 particular purpose gave indication that their use 

 could be extended to the solution of a far more im- 

 portant problem, viz, forecasting with some de- 

 gree of accuracy the flowering, ripening, and 

 stages in the picking of the cotton crop. In other 

 NO. 2^28, VOL. lOll 



words, an estimate of the yield of the crop could 

 be made several weeks before the cotton was ready 

 for picking. The line of argument for this conclu- 

 sion is fairly simple. The rate of the growth of the 

 plant in height (stem growth) was considered to 

 be, in some proportion, indicative of the rate of 

 flowering ; so that a curve of growth, compared 

 with some standard growth curve, would indicate 

 the rate of flowering three weeks before flowering 

 commenced. The flowering curve, in its turn (with 

 certain corrections), offered a ready means of esti- 

 mating the number of bolls of cotton, or the 

 amount of ripe cotton, that could be anticipated 

 two months later. Forecasting on these lines be- 

 came a scientific matter, and It held out a distinct 

 promise of a wide field of usefulness. 



The Ministry of Agriculture of Egypt evidently 

 determined to test this new method of forecasting 

 the cotton crop, and during the year 191 5 arranged 

 a number of stations in Egypt where the growth 

 of various classes of the cotton plant could be ob- 

 served systematically and complete data obtained 

 of their rates of growth, flowering, and ripening 

 of the bolls. The whole of the data thus collected 

 has now been published in the Agricultural Journal 

 of Egypt (vol. vli., 1917). An elaborate series of 

 curves has been graphed from the data. It Is appa- 

 rent that one of the chief objects of the whole 

 Investigation was the testing of the new method 

 of forecasting, for a statement is made to that 

 effect. In spite of this, however, no direct refer- 

 ence is afterwards made in the report as to the 

 effectiveness of the method, nor has an attempt 

 been made to express an opinion. 



The curves and data accompanying them have 

 evidently been considered by the Egyptian 

 authorities to be so adverse to this new method 

 of forecasting that they have deliberately refrained 

 from editorial comment. 



Whilst this particular feature occupies nine- 

 tenths of the report, it is evident from the 

 other sections, in the form of editorial 

 remarks and data, that previous to 191 5 cotton- 

 growing in Egypt was not conducted on cor- 

 rect lines, and that too strict an adherence to 

 Mendelian principles was not yielding the results 

 anticipated. In the editorial statements on this 

 feature the phraseology used is unfortunately 

 liable to misconstruction. It must, however, be 

 •conceded that further remarks on this feature 

 make it clear that whilst Mendelian principles will 

 be the basis of future work (this, of course, is 

 inevitable), consideration will be given to practical 

 factors accordino- to districts and local conditions. 

 The whole subject Is one of such practical utility 

 that someone should be associated with the 

 botanist to act as a guide in pointing out the 

 direction in which utility Is desirable. One or two 

 details of the report — for Instance, the measure- 

 ment of the fibres, etc., and the import of them, 

 the experimental spinning, and the interpretation 

 of the results — clearly indicate .the necessity for 

 complementing the staff of the Egyptian Ministry 

 of Agriculture dealing with cotton-growing by the 

 addition of a man thoroughly acquainted with all 

 the practical aspects of the cotton industrv. 



