52 



THE AGRICULTURAL NEWS. 



February 15, 1913. 



FRUITS AND FRUIT TREES. 



PRESERVING FRUITS FOR EXHIBITS. 



The following suggestions are made as the result of 

 incomplete ex[)eriments and with the consciousness that this 

 is only in the nature of a preliminary report, and barring 

 details will be found nevertheless to furnish a basis for 

 further experiments. Considerable success has been attained 

 along the-e lines in preserving specimens of Iruits, leaves 

 and twigs for the purpose of showing insect pests in situ, 

 ■with a natural condition of the plant, and it .seem.s certain 

 that the plan can be perftcted. 



The following is a brief outline for tentative working 

 basis for more experiment as to length of time for treating 

 and for proportions, all of which must vary according to 

 the .structure of the tissues of the plant specimen, or tlie 

 fruit and the amount of juices or sip present. 



(1) Immerse specimen in solution of copper sulphate, 

 1 part to .500 to 1,000 pure water, about three or four days. 



(2) Siphon ofT Huid, wash carefully by adding water 

 through tube reaching to bottom of the receptacle; siphon 

 ofi' the water and add in same manner more copper sulphate 

 solution, doable strength used first; let stand five to ten days. 

 If plant tissues are soft or pulpy, or rich in sugar, etc , add 

 to this solution one-half to one per cent, glycerine. 



(3) llemove fluid in same tuannt'r and let stand in pure 

 water twenty-four hours. 



(4) Itemove water and add solution of 10 per cent. 

 formalin, 1 to .500, plus 1 or "2 per cent, glycerine and 3 to 

 10 per cent, alcohol, and let stand one to three weeks. 



(5) Wash carefully as before. 



(6) Add final preserving fluid. For most specimens 

 solution of sul[)hurous acid 1 to 500 is best, to which may 

 be added if necessary glycerine and alcohol as with the 

 formalin solution. 



Instead of sulphurous acid, it may be best for certiin 

 specimens to u.se solution of formalin for final preservative, 

 or in some cases boracic acid, or even salicylic acid, while in 

 a few cases more or less alcohol alone or in combination is 

 required. 



This final solution needs to be changed from time to time, 

 whenever the growth of fungus forms a complete, firm, mouldy 

 scum on the surface of the Huid. 



A small air space is necessary in any sealed or glass-stop- 

 pered bottle to allow for expansion of tiuid at ditierent temper- 



atures. (The more succulent the specimen the weaker should 

 be the solutions of copper sulphate.) (The M<mthiy IhdUtin 

 of State Commissior. of Horticulture, December 1912.) 



THE ARTIFICIAL RIPENING OF BITTER 

 FRUITS. 



Professor Francis Lloyd, of McGill, related, in his 

 address to that university on October S, 1912, how, and the 

 reason why, astringency can be removed from bitter fruits in 

 fifteen hours by subjecting them to the action of carbon 

 dioxide under pressure. 



The idea is one that immediately attracts the interest 

 of both chemist and botanist. It appeals with equal 

 force to the instincts of the practical horticulturist and the 

 salesman. And moreover, the two kinds of fruit with 

 which these investigations have been chiefiy concerned — the 

 date and persimmon — grow naturally in the tropics and 

 sub-tropics, and a question arises at once as to whether 

 Professor Lloyd's treatment could not be extended, for 

 example, in the matter of improving the flavour of the 

 coarser varieties of West Indian mangoes and the various 

 wild fruits whose utilization as food is limited largely by 

 reason of their excessive bitternes.s. 



Professor Lloyd's address is published in Science for 

 December 27, 1912, ^.nd from that source the following infor- 

 mation has been abstracted. 



Astringency in fruits and other plant parts is due to the 

 jiresence of tannin in some form, very frequently tannic acid. 

 « )ne of the most ijeciiliar properties of tannin is its power to 

 enter into combination with many other substances such as 

 proteins, gelatins, mucilages and the like, to form complexes 

 (or compounds in a loose sense) which have in common the 

 peculiar property of resisting agents of decay. The usefulness 

 of tannin in the arts depends on this property. A vivid im- 

 jiression of this peculiarity is aflbrded by biting an astringent 

 fruit like the persimmon or an unripe banana. The tannin 

 in these will quickly attack and combine with the skin of the 

 mouth, causing what may be accurately and simply described 

 as a rapid manufacture of a thin coating of leather over the 

 mucous membranes. 



