February 



IRISH GARDENING. 



19 



important after all ? Take, for instance, the 

 treatment of insoluble calcium phosphates with 

 acids so as to render them soluble. Then to 

 get the best results the land must be limed so 

 that the soluble phosphate can combine with it 

 and become insoluble rather than combine with 

 substances more difficult to be rendered soluble, 

 or, should we say, more difficult to be digested 

 by the plant. Fineness for distribution again 

 seems the only advantage. Slag which con- 

 tains excess of lime over that in combination 

 with the phosphate (40 per cent, to 45 per cent, 

 total CaO) gives in general better results than 

 superphosphate when placed near the roots of 

 plants. Plants take in their food in solution, 

 but is it natural to suppose that a plant is left to 

 the chance of obtaining its food in this way 

 rather than preparing it itself? Since there is 

 an acid at the tips of root-hairs, and there are 

 ferments similar to those in the alimentary tract 

 of animals rendering soluble the food stored up 

 for the seedling, is it a wild imagination to con- 

 sider that there are digestive ferments in this 

 acid substance, so that, I'.g:, the dead microbe 

 which has stored up nitrogen in its bod}- can be 

 digested and used by the plant? Stimulants 

 act similarly on plants and animals. Certainly 

 plants have been grown on water cultures, but 

 what would be their nature after a few genera- 

 tions ? Soluble foods are also given to people of 

 weak digestion. The organs in question for the 

 succeeding race in both cases might be typified 

 in the nitro-culture w-here the microbe has been 

 treated either to a luxurious or a workhouse 

 life in a surrounding abnormal to what it was 

 accustomed, so that it no longer knows how, or 

 is not willing, to work for its food. Soils are 

 considered deficient in lime when they contain 

 less than i per cent. On farms we have a gene- 

 ral idea when lime is wanting by the appearance 

 of sorrel on cultivated lands, and on pastures 

 by the growth of foxglove, sorrel, moss, and the 

 dying off of perennial rye-grass and w hite clover, 

 their places being taken up by bent grasses not 

 relished by stock and showing a bleached 

 appearance even in summer. In testing soils 

 with litmus paper it is better to work with a 

 watery solution (distilled water in preference) 

 rather than placing the moistened litmus against 

 the soil. Blue litmus being the sodium salt of 

 the dye, the soda is more strongly absorbed 

 by the soil than by the paper, so that often an 

 alkaline soil may give an acid reaction. 



Besides precipitating the soluble phosphates, 

 lime is also useful in neutralising the acids left 

 after sulphate of ammonia has been nitrified 

 a'nd potash has been used by the plant. 



Crops on analysis show lime in less or more 

 quantities. Leguminous crops are most bene- 

 fited by lime. The gardener w'ho uses much 

 organic materials will find lime his best friend. 

 It ripens the wood and fruit in orchards. In 

 our use of lime let us look at the subject natur- 

 ally. Where organic matter is in excess hot 

 lime may be applied, as the destruction of 

 ammonia is a small part of the whole, but in 

 farm work, where our main object is to increase 

 organic matter, it is not wise to hasten its 

 decay too rapidly. 



[Note. — On page 4 of last issue in line 13 first column, and line 32 

 second column, please read magnesium oxide ; and line 19, instead of 

 CaCOHi) read Ca (0H)2 ; also last line but one read iidiorhd for 

 absorbed]. 



Another New Industry for Ireland. 



IN the last issued Kew Bulletin of Miscellaneous 

 Information there is an interesting article on 

 Rhamiiiis purshiana DC, one of the two Western 

 ."Vmerican buckthorns that supply the world with the 

 comparatively newly introduced drug cascara sagrada. 

 The commercial product is obtained from the bark, and 

 there has been such a demand for it since its introduc- 

 tion, about thirty years ago, that the trees in the native 

 forests are now becoming rapidly exterminated. 



\ suggestion being made thai an industry' for the 

 growth of this tree might be established in western 

 Ireland or Scotland, the Kew authorities have submitted 

 it to trial, and now declare that *' it seems not unlikely 

 that it may be a suitable subject for introduction to the 

 western coasts of the British Islands." They further add 

 that it " may also prove to be of value, commercially, 

 since the local supply is becoming exhausted and 

 plantations do not appear to have been started in 

 America." 



Having shown that the trees can be grown in this 

 country the Director of Kew, anxious to .satisfy himself 

 that the active principle of the bark that gives cascara 

 its peculiar tonic and laxative medicinal properties was 

 equal in quantity and quality to the native grown trees, 

 submitted the bark to a practical test. A tree, there- 

 fore, was cut down and the bark sent to the well-known 

 drug manufacturers, Messrs. Burroughs, Wellcome &' 

 Co., who worked it up into tabloids, and reported that 

 "the present extract is indistinguishable in its action 

 from that made from -American bark." 



There seem, therefore, to be reasonable expectations 

 from such an undertaking in the west of Ireland. 



The tree {Rhainnus purshiana) appears to vary con- 

 siderably as to size in its native home on the Pacific slopes, 

 but the largest specimen of the trees grown at Kew, raised 

 from seed sown in December, 1891, is now 21 feet high, 

 18 feet in the spread of its branches, and trunk girths 24 

 inches. They are "undoubtedly hardy at Kew." 



