210 



scratch or remove the outer cuticle. If this is broken through at any 

 one point, water will enter and spread to all parts of the seed, so that 

 a single scratch that penetrates the cuticle is sufficient to render a 

 seed permeable. This scratching is done with a file in the case of 

 large seeds, or in smaller ones by shaking them up with sand or pass- 

 ing them through revolving cylinders lined with cement in which sand 

 is imbedded. Another method is to treat the seeds with some strong 

 corrosive agent such as concentrated sulphuric acid, which if the 

 treatment is prolonged sufficiently, will completely remove the 

 cuticle. 



The second method is to remove the waxy substances from the 

 cuticle by certain chemicals known as fat-solvents, such solvents 

 are chloroform, ether or hot alcohol. This method is, however, not 

 practicable, owing to the expense of the solvents and the length of 

 time required to dissolve the wax, usually from three to four 

 months. The principle of soaking hard seeds in hot water to make 

 them swell may be explained in the following way: the effect of 

 the heat is to melt the particles Of wax which are distributed through 

 the wall. When they are melted they will tend to run together to 

 form larger isolated drops, and in this way spaces will be left through 

 which the molecules of water can push their way into the seed, caus- 

 ing it to swell and germinate. 



In the long list of seed that germinated or failed to germinate 

 after a long period of years the Acacias and Albizzias stand out as 

 very long lived. Acdcia acinacea, after 40 years, gave 55 per cent 

 germination. A. deciirrens after 16 years on immersion in acid for 

 hours, gave 100 per cent., and Alhizzia lophantha after 23 years all 

 germinated. 



The time required for the action of sulphuric acid at 12-15° C to 

 produce the swelling of the seed due to the permeation of water varied 

 with different seeds. In Albizzia lophantha it required 40 hours at 20 

 C, or 7 hours at 30° C, Indigo seed iltidigofera arrecta) required 15 

 to 30 minutes. 



The long duration of seeds in the ground only germinating when 

 the ground has been cleared and burnt over, is well known to many 

 persons. Ground is cleared and burnt over and plants which had not 

 previously been seen perhaps for very many years suddenly reap- 

 pear, the seeds having remained quiescent in the ground till the heat 

 of the sun or of fire has started them into germination. — Ed. 



ADULTERATION OF PRODUCE. 



The lo>s caused to the planter by the free use of adulterants of 

 his produce is one of those injuries which as a rule he does not appre- 

 ciate, yet it is nearly as injurious as the invention of a synthetic, the 

 idea of which hangs as a nightmare over him. Unscrupulous dealers 

 invent the most preposterous adulterants for tea, coffee, tobacco, 



