Vol. XII. No. 302. 



THE AGRICULTURAL NEWS, 



379 



RUBBER AND RUBBER PLANTING. 

 Lock, Sc I>. Camliridye f'liirersiti/ J'resn, 1913. 



In view of the fact that interest in the rubber industry 

 has extended within recent years beyond a comparatively 

 small section of the community directly connected with 

 production aud manufacture. Dr. Lock has attempted to 

 present an introductory outline of our knowledge of rubber 

 and rubber planting, in a form which is simple and yet com- 

 prehensive. The author has succeeded in doing this and 

 more, for the work is one which should be of great practical 

 use to those who contemplate entering the industry either 

 at home or abroad. 



In Chapter I, an account is given of the history of the 

 use and cultivation of rubber, where interesting statistics 

 relating to production will be found. la the next chapter 

 the botanical sources of rubber are dealt with, and a useful 

 description is given of the various latex [Toducing species. 

 Of particular interest in this chapter is the information relat- 

 ing to African and Asiatic rubbers, though the economic life 

 of these species, it is feared, is gradually drawing to a close. 



In dealing with the physiology of latex production, in 

 Chapter III, a large amount of attention is devoted, as might 

 be expected, to the laticiferous system. The subject-matter 

 is supplemented with illustrations showing the breaking 

 down of the lateral and transverse cell walls in I/erea 

 /,rasiliensis. In describing tapping experiments, Dr. Lock 

 brings together most of the reliable results on the subject. 

 Wound response is dealt with hrst, followed by duration of 

 yields. The relation of yields to volume of bark is a subject 

 of particular interest, and it is shown that in all probability 

 latex is formed by active secretion of latex in existing lati- 

 ciferous tissues. Seasonal variation receives attention next, 

 followed by an account of variation in the yield of different 

 trees. It is important to bear in mind the author's remark 

 that the selection of individual trees may be expected to 

 play an important part in the future development of the 

 rubber industry. 



A large amount of information is given next concerning 

 general considerations affecting tappings and yields, and 

 a useful summary of the po.-^ition is provided at the end 

 of the chapter. 



At the present day most of the easily accessible 

 land for rubber has alreidy been planted up, so that 

 the author's remarks on planting operations, presented in 

 Chapter V, should prove particularly helpful to those who 

 intend bringing new land under cultivation. The subjects 

 of clearing, nurseries, seed selection, drainage, irrigation, 

 roads, spacing, weeding, intercrops, manuring and the like 

 are dealt with in considerable detail. 



In Chapter YI, which deals principally with the methods 

 of tapping and the collection of the latex, Dr. Lock appears 

 to be at his best, and information brought together on this 

 branch of the subject constitutc^ a very valuable literary 

 contribution. 



The information relating to factory work, on the estate 

 deals principally with coagulation, washing, drying, smoking, 



etc. The facts presented in regard to coagulation seem, to 

 be rather limited in number, and some of the more recent 

 work is apparently not incorporated in this section. The 

 last three chapters deal respectively with pests and diseases 

 of Hevea, the chemistry of India rubber, and the manufacture 

 of rubber goods. The mycological information is principally 

 composed of the results of Fetch's work in Ceylon, whilst the 

 chemical information incorporates the fundamental facts 

 concerning synthetic rubber and the physical properties of 

 caoutchouc. The inclusion in the final chapter of a des- 

 cription of the principal processes involved in the manu- 

 facture of rubber goods completes the intellectual j jurney; 

 the reader having travelled from the wild territories of the 

 Amazon to the plantation in the East; from the fields of the 

 plantation to its factory; and from there to the large manu- 

 facturing establishments at home, where the raw material is 

 tested and turned into marketable articles. 



THE CORN CROP. By E. G. Montgomery. The- 

 Macmillan Company, New York, 1913. 



Yields of Indian corn amounting to 200 bushels per 

 acre have under optimum conditions been produced in the 

 United States, though the average yield is, at present, about 

 26 bushels. Therefore the study of Indian corn should be 

 directed towards those factors which hinder full develop- 

 ment and thus limit production on the average farm; and it 

 is from this point of view that this useful text book deals 

 with the subject. It should be added here, that the author 

 does not confine himself to Indian corn alone, but devote.'t 

 several chapters also to sweet corn and the sorghums 

 (including broom corn). 



The subject of plant adaptation is treated in a very 

 instructive manner. The improvement of varieties by mass 

 and pedigree selection, and by selection based on chemical 

 composition is dealt with first, followed by directions for 

 laying out experimental plots. All the information is 

 essentially practical. The chapter on the results of hybrid- 

 ization deals with the crossing of biotypes and the appli- 

 cation of Mendel's law, and the section concludes with 

 an account of the manurial requirements of corn. The 

 succeeding section deals with cultural methods, the principles 

 of which apply to a certain extent in the Tropics 



The preparations for planting the corn crops in the United 

 States should (though do not always) include the 'ear testing' 

 of the seed to be planted. A piece of wet cloth is divided 

 by lines into square inches, and from each ear of corn 

 intended for use as seed, six grains are taken. Every six 

 grains is placed in a single square and the ears whose grain 

 germinates quickest, bear the seed that should be used for 

 planting. 



In perusing Chapter XIX, concerning the harvesting of 

 corn, we hoped to find rather more space devoted to the 

 question of storing and drying of corn. Little is said on this 

 subject, beyond the fact that large commercial driers are 

 now in general use. 



In regard to the export trade in Indian corn from th& 

 United States and other countrie.s, a large number of inter- 

 esting statistics are given. The exportation of corn from the 

 United States is decreasing: it has fallen in ten years from. 

 9'4 per cent, of the total crop to only 229 per cent. This 

 decrease indicates that home consumption in the United 

 States will soon equal production. Countries (e.g. the VVest 

 Indies) which can grow lorn but choose rather to import moat 

 of what they use from the United States, would do well 

 to bear this in mind. 



