March i, 1884.] 



THE TROPICAL AGRICULTURIST. 



63s 



growth of its own ;. hence, in grafting apples, plums, vines, 

 roses, and other plants, the rule has been to employ the 

 root of the stock only, with sometimes a portion of the 

 stem, as in the case of standard trees and roses, &c. For 

 some time, however, the fact has been giadually forcing 

 itself on the minds of gardeners, that by this method the 

 value of the stock is greatly impaired, if not lost in 

 numerous instances. It is found that by grafting a weak 

 - variety on another and stronger variety, a more vigorous 

 growth is the result at first, but that in the end, and 

 sometimes very soon after, the graft becomes just as weak 

 as if it had been on its own roots. The reason of this 

 is plain on reflection. A sti-ong root produces a strong 

 top growth, and while the strong top remains and extends 

 the root extends reciprocally in the same ratio. When, 

 however, we cut the top off and substitute by grafting 

 another and weaker top in its place, the root is for the time 

 paralysed, and never afterwards does more than respond 

 to the weaker growth grafted on it. This is very easily 

 demonstrated in the case of the vine, numerous examples of 

 which the writer has seen. I more than suspect, too, that 

 the reason why the quince and paradise- roots require so 

 much pruning in this country is, that wliile they do restrain 

 the luxuriance of the strong-growing subjects grafted on 

 them, they are at the same time acted upon reciprocally, 

 and made to grow stronger than they would do if they bore 

 their own natural and less vigorous branches. A corre- 

 spondent, in writmg on dwarf stocks for apples years ago, 

 said they should •' furnish a dwarf and fertile growth 

 without any root()runing whatever ;" and this is what was 

 expected of them in culture, and what theorists said would 

 happen, but it is founu that such trees require regiUar root- 

 pruning uniler some circumstances. On the other hand, it 

 may be well beUeved that the crab and pear stocks are 

 enfeebled by having weak varieties worked upon them in 

 the reverse way. 



The general conclusions I draw from observations are, 

 that the root of a stock alone, when a more vigorous gro^vth 

 in the scion is desired, is of very little use ; that the way 

 to get the benefit of the union is to allow a portion at 

 least of the foliage of the stock to grow as well as the 

 scion; and that it would be advantageous, and certainly 

 not injurious, to graft weak varieties with stronger ones 

 at both ends, which may be considered a species of 

 double grafting, but not in the sense in which that term 

 is used generally, which means grafting one variety on the 

 top of another, and only allowing the last to grow. Lastly, 

 I believe that none of the dwarfing stocks, like {he quince 

 or paradise for example, wlU maintain trees in a per- 

 manent state of fertility at least, till the treesj acquire age 

 and have overgtown the stock, but must be root-pruned 

 only in a less degree than the crab stock, especially the 

 quince, which produces stronger pear trees than the para- 

 <lise does apples. This is my experience here in our cool 

 soil and climate. All our quince stocks have been primed 

 over and over again, and their roots are always found to 

 be just in proportion to the vigour of the aUen top they 

 bore.— J. S. \Y. — Field. 



GUTTA-PEROHA. 



BV JAMES COLLIXS. 



The earhest notice concerning gutta-percha I have come 

 across, is contained in .Tohn Tradesc.int's catalogue of his 

 "Rarities preserved at South Lambeth."" In this is men- 

 tioned " plyable mazer wood, being warmed in water, will 

 work to any form." It is also by no means impossible 

 that some of the historical " mazer cups " may have been 

 made from this maturia!,+ the mottled ajjpearance of gutta- 

 percha answering to the descriptions given, and its hght- 

 ness, strength, and non-liabiUty to fractm'e, would render 

 it a good substitute for the true maple. " Mazer-wood 

 tree " is also one of the vernacular names of the gutta- 

 percha tree. 



To Dr. William Montgoraerie, a surgeon in .the East 

 India Company's services, belongs the honor of first bring- 

 ing this substance before the commercial world. He iii'st 

 noticed it in Singapore m 1822, and experimented onjt ; 



' " Museum Tradescantium."— London, mdci.vi, 



I I'ide Spenser's " Shephearde's Calendar," and " Faerie 

 Queeue." 



and in 1842, whilst again in Singapore, he recommended 

 it to the Jledical Board of Calcutta as a substance use- 

 ful in the making of surgical sphuts. He also sent sam- 

 ples to London to the Society of Arts, who warmly took 

 up the subject, and, in 1844, awarded Dr. Moutgomerie 

 their gold medal. In 1843, Dr. (afterwards Hir) Jose 

 d'.iUmeida sent a sample to the Royal Asiatic Society, 

 and some persons have confounded these two circumstances. 

 Dr. d'^Vlmeida, it should be remembered, sent gutta-percha 

 as a ciu-iosity, whilst Dr. Montgomerie, long before this 

 date, experimented on the substance, and recommended it 

 as likely to prove of great utihty in the arts and manu- 

 factures. 



In 1847, Sir W. J. Hooker* named the jjlant Isomndra 

 gutta, from specimens supplied by Mr. Lobb, who was at 

 that time collecting plants for the Messrs. Veitch, the 

 eminent nursei-ymen ; and Jlr. Motley, whilst in Borneo, 

 added materially to our information. Dr. de Vriese, on 

 the part of the Dutch Government, did good work in this 

 direction, he giving descriptions of eighteen plants yield- 

 ing this substance.t 



Gutta-percha, as it appears in commerce, is of a reddish 

 or yellowish hue, nearly as hard as wood, and of a porous 

 structure. 'WTien cast or rolled, it as.sumes a fibrous struct- 

 ure, and acquu-es a tenacity in a deteiminate du-ectuin. 

 At a temperature of 32= to 77° Fahr., it has as much 

 tenacity as thick leather, but not at all elastic, and less 

 flexible. In water, towards 120 ° Fahr., it softens and be- 

 comes doughy, although still tough; at 145° to 150° 

 it becomes soft and pHant, assuming the elasticity of 

 caoutchouc, becoming again hard and rigid on cooling. It 

 is highly iutlamiiiable, burning with a bright flame, and 

 its electrical properties are well known. 



Gutta-percha, like many other milky juices, is found 

 stored up in an irregular network of tubes {Ciiienchi/mu, 

 or lactiferous tissue), in the middle layer of the bark; 

 the outer layer, largely developed in the cork oak, is 

 known as the corky layer, or ejnphleum, and the inner, 

 Im-gely developed in fibre-plants, is known as libei-layer, 

 or endophUum. Thus the bark has to be cut mto to free 

 the milky juice. 



Gutta-percha trees are confined to the natural order 

 Sapotacea;, an order yielding succulent fruits, such as the 

 sapodiUa plum (Acliras iuputa), vegetable butters as from 

 the seeds of various species of Jjassiu, whilst from species 

 of Dichopsis (Jsonandnt), and other genera, we have the 

 peculiar gum-resm, or hydrocarbon, known as gutta-peicha. 

 A short description of the better known tree will be suf- 

 ficient for the present purpose. 



llk-hopsis r/utta (Jsonandru t/utta) is known under various 

 names, such as gutta-percha, gutta tabun (the more coi- 

 rect), gutta durian, gutta uiato, and many others. The 

 word gutta, gutah, gatta, gittah, as it is variously spelt, 

 signifies in Malay, gum or juice. The second name is the 

 name of the tree producing this gum, the same tree hav- 

 ing a different name in ditfereut localities. The tree is 

 found in the Malay Peninsula, Sumatra, Borneo, au>l 

 throughout the Malayan Archipelago generally. It g^ow.^ 

 to a height of 6« to SO feet, with a diameter of 2 to h 

 feet. The leaves are inversely egg-shaped and entire, pale 

 green on the upper side, and covereil beneath with a 

 reddish-brown shuiiug down. The flowers are arranged in 

 clusters of three or fom- in the axils of the leaves. The 

 fruit is a small oval berry. The gutta, as it flows from 

 the tree, is of a greyish colour, at times somewhat roseat. 

 in hue, possibly arising from the cokur of the bark. 

 There is also an oblong leaved variety of this species. Ot 

 other kinds mention may be made of the following:— 



JJickopsis maavphi/lla, the Ngiato putih or white gutta- 

 percha of Borneo, the gutta of which, accortling to Motlev, 

 is of a seconil-rate quality. 



Dichopsis Jiotlei/iimi, yielding a very low kind, known as 

 gutta kotian (Motley). 



lUii/ena dasi/plii/Ua, yleldiivg a second-rate quality, known 

 as gutta benton', in Borneo (Motley). 



I'ui/eiia Leeri, yielding gutta balem-taiuloek, &c., in Su- 

 matra and Java. 



Besides these there are species of Ohrii <ophiiUum, Inder- 



» "Lond. Jour. Botany," Sept. 1847, p. 104. 

 •j- Dr. Vriese, I'lautie Batavas Oritutalis, Lug. Bat. 1,'-5U ; 

 Do Haudcl iu Getah-Pertja, 1856. 



