Vol. XII. No. 266. 



THE AGRICULTURAL NEWS. 



1-21 



The trade in fresh limes wivh the United States 

 of America continued to be steady. During 1912, 

 t).5,()4() barrels of limes had been e.xported to New York 

 compared with o4,:U<J in 1911. and 25,.509 in 1910, 

 This traile had been built uji from the shipment of 

 (),8^i4 barrels exported to the United States in 1902. 

 The trade in fresh limes with the United Kingdom and 

 with Canada could not be said to be on a satisfactory 

 basis; the exports last year to these places being respec- 

 tively 1,32-3 and 801 barrels. 



His Honour was advised that the lime and cacao 

 crops of the island for the present year promised well, 

 and that it was anticipated they would give a larger 

 3'ield than during the past year. With the present 

 market prices foi- these commodities, the prospects of 

 the island were good. 



Maize with Silks Maturing before Tassels. 



A discovery has been made in America of the 

 proterogynous habit in a variety of maize introduced 

 from Granada, Spam. In plants of this type the silks 

 are exserted and recejitive before the pollen begins to 

 fall. In the publication where this information is pre- 

 sented (Cirfulur No. 107, United States Department 

 of Agriculture) it is further pointed out that the 

 proterogynotis characteristic insures a much larger per- 

 centage of cross-pollinated seed than is obtained in the 

 ordinary varieties in which the falling of the pollen is 

 simultaneons with, or precedes the essertion of the 

 silks. If this character could be combined with improved 

 American types it would obviate the necessity of detas- 

 selling to secure cross-pollinateil seed. A small quantity 

 of pure seed of this variety has been produced during 

 the past season in America, and is available for those 

 wishing to undertake the introduction of this character 

 into local varieties. 



^Fhe Watering of Cuts in Rubber Trees. 



A paper has recently been published in the 

 Agricultural Bulletin of ike Fed) rated Malay States 

 \\o\. I. No. 7) which is important from two points of 

 view. In the first place it contains results that are 

 likely to be of practical value, and in the second place 

 it atfords an example of an original investigation that 

 has been undertaken by a planter. The Hrst experi- 

 ment in the investigation was designed to show 

 whether the commonly practised custom of watering 

 cuts lengthened or shortened the duration of the dripp- 

 ing period. In round numbers it was found that when 

 the cut was watered the tree continued to drip for 

 eighty-one minutes, when the cut was rot watered, for 

 102 minutes: that when the tree was watered it yielded 

 350 drops, when not watered 510 drops. A second 

 and more extensive experiment led to the astonishing 

 conclusion that one thousand trees would give about 

 ^-ft. less rubber a day if water were poured on the cuts 

 "than they would give if the cuts were not watered. 



The rciison fur this appears to be that the a<ldition 

 ••of water induces coagulation. 



Formation of Resin. 



In AiiiuiIm da Must'e C<jli)nial de Mtir.sielle, 

 Vol. X, 1912, appears an interesting paper by Jadin 

 and Juillet on theit research into the anatomy of three 

 species of Kalanchoi' of .Madagascar. The genus Kalan- 

 choe belongs to the natural order Crassulaceae which is 

 closely related to the Cactaceae. To the Oassulaceae 

 also belongs the genus liryophyllum which has a repre- 

 sentative in the West Indies, BryopliyUum calycinum 

 (love bush). 



The stems of the species of Kalanchoii examined) 

 contain scented resin, and the most interesting feature 

 of the investigation was the study of its formation 

 which begins with the suberization (or cork-formation) 

 of the layer (jf cells immediately below the epidermis or 

 skin. For some time the nuclei of these thickened 

 cells remain alive, but eventually they disappear and 

 their place is immediately taken by the scented resin. 

 Sometimes this substance apjJears in the interior cells 

 of the stem, but it is them immediately replaced by 

 large crystals of calcium oxalate. 



The suberization and resin-formation function as 

 xerophytic characters to provide against excessive 

 transpiration It is not stated whether the resin is of 

 any economic value. 



Identification of Vegetable Oils. 



T'he following methods for the identification of 

 two important vegetable oils appears in the Agricul- 

 tural Ledger 1911-12— No. 5. 



Dealing first with cotton seed oil it is pointed 

 out that this is I'eadily recognized by the high 

 melting and solidifying points of its fattj' acids. 

 There are also certain colour reactions which are 

 employed in analysis. The Halpen colour reac- 

 tion is the best, and is applied as follows: 1 to 

 3 c.c. of oil is dissolved in an equal volume of amyl 

 alcohol; to this is added 1 to 33 c.c. of carbon bisul- 

 phide holding in solution 1 per cent, of flowers of 

 sulphur. The test tube containing the mixture is then 

 immersed in boiling water. The carbon bisulphide 

 evaporates off, and the cotton seed oil gives in the 

 course of five to fifteen minutes a deep red colouration. 

 This reaction is very characteristic, and it is possible 

 to detect thereby 5 per cent, or even less of cotton seed 

 oil in admixture with other oils and fats. Ivapok oil 

 (from Eriodendron anfractuosura) possesses similar 

 properties but its fatty acids melt at a rather higher 

 temperature (4<1 C). 



Arachis oil from the ground nut {Aracltis hypogaea) 

 can be identified and detected by the isolation of 

 arachidic acid, a constituent melting at 74 .j C. Aboutj 

 10 grams of the oil is saponified, neutralized and 

 treated with lead acetate. The lead salt is extracted 

 with ether, the insoluble portion is decomposed, and 

 the fatty acids dissolved in 50 c.c. of 90 per cenf^ 

 hot alcohol. On cooling the alcoholic solution, a crop 

 of crystals w'ill be obtained which should amount to -^ 

 per cent, of the oil, and should melt between 74' and 

 75o C. 



