•Vol XI. No. 270. 



THE AGRICULTURAL NEWS. 



2S1 



Silkworm Industry, 1912. 



The world's production (if silk during the present 

 year is likely to be very satisfactory, thoiii^h it is 

 estimated that the yields will be somewhat below those 

 of 1911. It is stated in the Bulletin of Agricultural 

 Statistics ot the International Institute of Agriculture, 

 Vol. Ill, No. 7, that ill Austria and in France the 

 harvests have been particularly good, but in Hungary 

 the production has been somewhat limited owing to 

 the spread of disease as the result of a wet season. 

 The following figures, given in the above journal, 

 represent the total production of cocoons in Kurope, 

 Asia and Africa: obtained in lOl I, 140,026.109 kilos; 

 estimated in 1912, l:vS,224,ti.J3 kilos. It is expected 

 that the production in 1912 will be just under that of 

 she previous year. 



Pruning Sea Island Cotton. 



The Annual Repoic of the Hawaii Agricultural 

 E.xpeiiment Station for July 1, 1910 to July 30, 191 1, 

 issued April 9, 1912, to which reference has been made 

 Uready in the Agricultural Xetrs, gives attention to 

 the subject of the ])runing of Sea Island cotton, which 

 has received some investigation in Hawaii. It states 

 that, after the plants had been pruned back to mere 

 stumps, some high and some low, the new growth 

 always started from near the ground, showing that if it 

 is desired to grow Sea Island cotton as a perennial, 

 Jew pruning should be practised: it is also necessary to 

 plant it wider than usual (8 feet by 5 feet) to give suHi- 

 cient room for cultivation and picking. 



In the experiment that is described the plants, 

 •ifter being cut back in December, bloomed pro- 

 fusely in the spring, and it seemi'd that there would 

 he a good crop; attacks of the boll worm and of mealy- 

 bugs caused the bolls to be shed, however, and the 

 latter pest infested the plants so severely in some cases 

 that they had to be destroyed. 



The only additional pruning that was practised 

 ^vas that a few of the plants were pinched back just 

 before the bolls began to form; the result was that the 

 plants that had been pinched back Howered much more 

 profusely and somewhat earlier than those which had 

 not been so treated. The first picking was made on 

 June 15, 1911, and at that time the boll worm was 

 present in great numbers. 



Adsorption of Certain Substances by Starches. 



Most porous bodies, like colloids, coagulated 

 a,lbumen, wood charcoal and starches, on account 

 of their surface 'tension', po.ssess the ability to take 

 Tup certain substances in sui/h a manner that the 

 aiiaterial taken up cannot be removed, even by 

 Tnost thorough washing. This phenomenon is called 

 .-adsorption. An interesting account of investigations 

 on the adsoi'ptive power of different starches appears 



in the Journal of ili,e American Chemical Soci*. 

 ety, Vol. XXXIII, No. 7, and since several of the 

 starches examined were obtained through the Imperial 

 Department of Agriculture, from the West Indies, 

 a statement of the conclusion.s arrived at is likely to 

 prove of interest. 



The starches used in the investigation were 

 cassava from St. Vincent and from St. Lucia; arrowroot 

 from different estates in the West Indies — chiefly froni 

 St. Vincent; and potato, rice, and maize starches 

 obtained in the United States. 



The object of the e.xperiments w-as to test the 

 adsorption by starch of three substances, hydrochloric 

 acid, sodium hydroxide, and sodium chloride. 



The conclusions arrived at were as follows: '(1) the 

 adsorption of hydrochloric acid, sodium hydroxide and 

 sodium chloride by starch, \aries with different starches 

 but not as much as would be expected considering the 

 great differences in the size of the granules. (2) The 

 adsorption is not regulated by the granule surface per 

 unit of weight. (3) The amount of adsorption is much 

 greater for sodium hydroxide than foi- either hydro- 

 chloric acid or sodium chloride. (4.) In the case of 

 starch-hydrochloric acid the ordinary adsorption rule 

 is followed for solutions up to abou'. 04 sionnal. except 

 in the case of maize starch.' 



Changes in Plants Through Continued Vegeta- 

 tive Propagation. 



The changes that take place in plants through 

 continuous vegetative reproduction have often excited 

 great interest; in the West Indies the matter has gained 

 much importance particularly in relation to the sugar- 

 cane which, especially with what are called the newer 

 varieties, shows a tendency to degenerate after it has 

 been raised from cuttings in the ordinary way for 

 several seasons. 



The matter has also been proved to be important 

 in relation to fruit trees: the English physiologist 

 Knight has shown conclusively that these change manj- 

 of their characteristics when grafted repeatedl}', the 

 change often tending in the direction of degeneration. 

 Such degeneration, with respect to another case, takea 

 place with great rapidity in the potato, as is well 

 known. 



To pursue the subject, the Bulletin of the Bureau, 

 of Agri<:ultural Intelligence a ad of Plant Diseases, 

 for June 1912, contains a short abstract of a paper 

 describing work in the vegetative reproduction of the 

 chrysanthemum. In the investigation, a variety of 

 this plant was grown for eighteen years, being repro- 

 duced by means of slips alone. The author's observa- 

 tions appear to show that a new variety inferior to the 

 original was obtained, although the continued reproduc- 

 tion was made under constant conditions; further, it 

 seems that the variation was progressive and not 

 sudden. The latter circumstance affords an example 

 which supports the theory of the existence of 'slow 

 varieties' capable of yielding many new types — an idefv 

 originated and developed by Darwin and Lamarck. 



