66 Effect of Boron Compounds 



Reinette " apple to -06 % in figs. Bechi had previously (1891) detected 

 boron in the ash of figs, love-apple, and rubus finiits fi:om Pitecio, but he 

 attributed this to the presence of boric acid or borates in the soil at the 

 place. 



Passerini (1891) found traces of boron in the stems of chickpea 

 plants, while in 1892 Brand determined boric acid in the ash of beer. 

 In consequence of this various samples of hops were ashed without the 

 addition of any alkali, and then the ash was distilled with sulphuric acid 

 and methyl alcohol. When tested all the hops showed relatively large 

 quantities of boric acid in comparison with beer, hence he argued that 

 the boric acid in beer is derived fi:om the hops. Boron was discovered 

 in various parts of the hop plant — in the clusters, leaves, pedicels, and 

 stems. 



Jay (1895) analysed many plants and plant products grown in various 

 soils and waters, and arrived at the conclusiop that boron is of practically 

 universal occurrence in the plant world. Of all vegetable liquids wines 

 are the richest in this constituent, the amount varying fi-om "009 gram 

 to "33 gram per litre. He confirmed Hotter's statement as to the 

 richness of finiits in this substance, finding firom 1"50 — 6"40 grams in 

 1 kgm. of ash. Chrysanthemums and onions, amongst other plants, are 

 well off in this respect, containing 2"10 — 4'60 grams per kgm. of ash. 

 Jay also found that the plants vary in their capacity for absorbing boric 

 acid, those which do so the least easily being Gramineae (as wheat, 

 barley, rice), mushrooms and watercress, the quantity in these plants 

 never exceeding '500 grams per kgm. of ash. 



Of all the workers upon boron, Agulhon has done the most to extend 

 and concentrate our knowledge of the subject. He used the most re- 

 fined, up-to-date methods for the detection and estimation of boric acid, 

 and so determined its presence in many plants, including angiosperms, 

 gymnosperms, ferns, algae, and fungi. Tobacco is so rich in boron 

 that it can be detected in the ash of one cigarette. Among the plants 

 tested, the highest percentages of boric acid were found in Betula alba 

 (1'175 % of ash) and Laminaria saccharina ("682 % of ash), the lowest 

 in Cannabis sativa ("123 % of ash). Generally speaking annual plants 

 and parts of plants seem to have the least boron in the composition of 

 their ashes. In one and the same plant the durable parts like bark and 

 wood are richer than the leaves, even in evergreen trees. He indicated 

 that plants seem to have a great affinity for boron, as even when plants 

 are grown on soils in which the boron is practically indetectable they 

 .always seem to extract an appreciable quantity of the element. 



