March 2, 19 16] 



NATURE 



lysis, the sugar content has been increased from 

 an average of 15' 2 to one of i8'5 per cent. 

 Individual roots have contained from 26 to 27 

 per cent, of sugar, and there is every reason to 

 believe that the improvement of the beet is far 

 from having reached its limit. 



It is impossible here to do more than glance 

 at the latest methods of working adopted by the 

 seed-selecter. Each single root grown has its 

 sugar content determined by a process which 

 leaves it practically uninjured and suitable for 

 planting after its character has been ascertained. 

 The small sample of pulp is taken for analysis 

 by means of a small rasp-drill which pierces the 

 root about 2 cm. below the base of the neck at 

 an angle of about 45°. Experience has shown 

 that although the sugar content is very different 

 in different zones, the particular section taken in 

 this way corresponds with the average over the 

 whole root. 4"o65 grams of the pulp so obtained 

 (one-quarter the " normal " weight) are transferred 

 to a 50 c.c. measuring flask, and water, con- 

 taining basic lead acetate, added, so as to make 

 the volume about 40-45 c.c. After adjusting ex- 

 acdy to 50 c.c. and filtering, the solution is exam- 

 ined in a 400 mm. continuous-flow saccharimeter 

 tube. In this way the percentage of sugar in the 

 root is read off directly on the instrument. 



As a result of the analysis the roots are divided 

 after lifting into three classes: "mothers," 

 "grandmothers," and "elites." Thus, in the 

 case of the 191 5 crop, mothers and grandmothers 

 would be used to furnish commercial seed, the 

 "mothers" in 1916, the "grandmothers" in 

 1918. The "elites" would, in 1916, give seed 

 which, in 1917, would yield the supply of roots 

 to be again subjected to selection. 



From time to time the selecter comes across 

 roots the characteristics of which stand out as 

 abnormally desirable. Such plants are subjected 

 to careful genealogical selection in order to 

 ascertain whether their descendants show these 

 qualities on even a greater scale. If so, these 

 roots are made "heads of families" and are the 

 starting-points of new and improved races. Pro- 

 gress in the future largely depends on discover- 

 ing remarkable "heads of families." For such 

 a result it is necessary, not merely for the operator 

 to be skilled in selection, but he must work on 

 enormous numbers of roots — several hundreds of 

 thousands each year. 



A field of future work, which as yet has 

 scarcely been touched, lies in an attempt to avoid 

 the injurious effect of cross-fertilisation, which 

 tends to retrogression of the race. Another rich 

 opportunity for work is to be found in the adapta- 

 tion of beet seed to local soils and climatic con- 

 ditions. For this purpose it would be necessary 

 to carry out the experiments with the seed plant's 

 m the localities where the main croos are subse- 

 quently raised for the sugar manufacturer. 



One of the most promising directions for future 

 work in improving the sugar beet is to be found 

 in the asexual method of propagation suggested 

 by Nowoczek and adopted with success by M. \ 

 NO. 2418, VOL. 9;] 



Gorain at Offenkerke and M. Helot at Noyelles- 

 sur-Escaut. In this system multiplication is 

 effected by grafts and buds in the individuals 

 used to give the seed of the first generation of 

 "heads of families" and "elites." Full details 

 are given in M. Schribaux's paper of this system, 

 which has the great advantage of rapidly in- 

 creasing the number of the specially desirable 

 individuals to be subjected to further selection. 



Many other problems face the seed-selecter in 

 France which are dealt with in considerable 

 detail, more particularly that of the improvement 

 of the germinative power of the seed and the best 

 means of rapidly producing in France at the 

 present time the necessary supply of high-grade 

 seeds, which in the past were largely imported 

 from abroad. W. A. D. 



lUE RECENT MORTALITY AMOXG BEES. 



HOME industries and home sources of food 

 supply are to the fore under the present 

 conditions of war. Wastage of native food 

 sources seems to arise from two main factors, 

 namely, ignorance and carelessness. The serious 

 loss of home-produced honey owing to bee dis- 

 eases, more especially " Isle of Wight " disease 

 and foul brood, is largely to be ascribed to the 

 two human failings just mentioned. 



^^'hen epidemics of known origin occur in man 

 or vertebrates, such as cattle, there are well-known 

 rules the prompt application of which stops the 

 outbreak. Two prominent preventive measures 

 are destruction of the source of the infection and 

 segregation of the infected individuals and of con- 

 tacts with them. It is safe to say that had such 

 measures been rigorously enforced when " Isle of 

 Wight " bee disease was first observed in England 

 about 1904, the great mortality recenth' occurring 

 among bees at Peterborough, as well as in other 

 parts of Great Britain, would not have arisen. 



While several diseases are prevalent among 

 bees at the present time, the so-called " Isle of 

 Wight " disease is responsible for much of the 

 damage. The disease is parasitic in character, and 

 a minute, one-celled animal organism, Nosema 

 apis, has been shown to be the causal agent. The 

 life-history of the parasite and the mode of infec- 

 tion were elucidated by Drs. Fantham and Porter 

 in 191 1, and they have also engaged in researches 

 on the prevention and cure of the malady. 



The life cycle of Nosema apis may be com- 

 menced conveniently with the resistant, infective 

 spore form of the parasite. When some of the 

 contents of the food canal, or the excrement of a 

 bee suffering from the more chronic form of the 

 disease, is examined microscopically, small, rice- 

 grain-like, shining bodies are seen, mingled with 

 pollen grains in various stages of digestion. These 

 small bodies are the spores, which are about one- 

 thousandth the size of an actual rice grain. They 

 have a tough, resistant coat, and. when set free 

 from the body of the bee, can live for a long time. 

 If they are carried by the wind into water at which 

 bees drink, or if they contaminate honey eaten by 



