4H 



THE TROPICAL AGRICULTURIST. [Dec. i, 1885. 



I have heard a great rlcal about the glories of the 

 ''Croklen State;" but what strikes me as beiug most 

 iucousistent with a " goUleu " comhtiou of things is 

 the presence of so many tramps looking for work — ■ 

 swagmeu as they are termed in Australia, the swag 

 beiug a bundle of blankets carried at the back. 

 — 0. II. Godfrey, Napa, California. 



♦ 



" MADAB." 



BY C. J. H. WARDEN (ON FURI.OI'RIl) .\ND L. A. WADDEL, 



Surf/eons H. JI.'s Bciuitit Army. 



Botanical Chiii-acters. — In India, under the popular 

 name of "Madar," two plants belonging to the N^it. 

 Ord, of Asclcpiadiaceio are known — the ( 'nlotrojiis 

 yiyaidea-f or Aadepia'^ gigantca, and the Cahtropis 

 procera, or C. Hami/tonii. The former is one of the 

 commonest weeds throughout India, and is most 

 abundant in the lower provinces and Eastern India; 

 while the C. procera, which most closely resembles 

 it, is found chietiy in the drier parts of Northern 

 and Central India. Botanically, the C. yii/antea is 

 thus described by Drury* : — ^Shrub 6-10 feet; leaves 

 stem-clasping, decussate, eblong-ovate, wedge-shaped, 

 bearded on the upper side at the base, smooth on 

 the upper surface, clothed with woolly down on the 

 under side; segments of corolla retle.fed, with re- 

 volute edges; stamineous corona 5-leave(l, shorter 

 than the gynostegium ; leaflets keel-formed, ciroiuately 

 recurved at the base, incurved and sub-trideutate 

 at the apex ; umbels sometimes compound, surrounded 

 by involucral scales ; follicles ventricose, smooth ; 

 seeds comose ; flowers rose-colour and purple mixed. 

 Flowers all the year. Both varieties grow well on 

 the poorest soils, and are largely cultivated in some 

 parts of the country as a hedge (Watt). * ♦ 



Emnvmic- Uses. — Certain of the ecouoraic uses of 

 the madar plant have already been noticed, and we 

 would here refer to the employment of the inspis- 

 sated sap as a substitute for gutta-percha, and to 

 the use of the fibre for paper making. Dr. G. Watt, 

 in his work on 'The Economic Products of India,' 

 states that madar is, in fact, the most interesting 

 and most hopeful plant not belonging to the natural 

 (U'llcr of Saijotacere, which can be said to yield a 

 substance resembliug gutta-percha, ever likely to obtaiu 

 a commercial reputation as a substitute. Dr. Riddell, 

 the Superinteudeut Surgeon to the Nizam's army, 

 was apparently the first to separate and experiment 

 with this gum, and his results were first [jublish- 

 eil by Captain (the late Colonel) Meadows Taylor, 

 in a letter to the Secretary of the Agri-Horticultural 

 Society of India.f Afterwards, Dr. Kiddle republished 

 his discovery in the Homhai/ l\mis. As these letters 

 may not be accessible to persons bkely to be 

 interested by this subject. Dr. Watt republishes the 

 more important parts, narrating the actual experiments. 



" My dear Sir, — I observe in the last number of 

 the tiocietifs Traiisratiuns, that the mM\iir—Ascl»pia 

 (/i'yffHtea— affords a very valuable kind of hemp or 

 "flax, and I have now the pleasure to communicate 

 to you another valuable property it possesses, which 

 has beeu lately discovered by a friend here, under 

 whose permission I make the present connnunicatious 

 to you. 



"Dr. lliddell, the ofliciating Superintendent Surgon 

 of the Nizam's army, had for some time been employed 

 in extracting or determining by chemical experi- 

 ments, the well-known medicuial properties of this 

 plant, and during his investigaficni, having ^ had 

 occa.siou to collect the milky .■^ap, and expose it to 

 the air, fouud, as it gradually dried, that it became 

 tough and hard, and not unlike gutta-peri'ha. This 

 iiuhiced him to treat the juice as that of the gutta- 

 pcircba tree is ilone, and the result has been the 

 obtaining of a substance apparently [irecisely aualogous 

 to gutta-percha, of which 1 have the pleasure to 

 send you a specimen, beariug the impression of his 

 seal marked No. I. 



" The mode of preparing this substance is as 

 follows; — _ 



« ' Useful Plants of India.' 



•)• Ayri-Uortic. Soc. Journ., vol. viii. 



" The juice or sap to be collected by iucisiou. An 

 open slit may be made in the birk, and a pot tied 

 to it, when the jiuce will How into it; or it may 

 be collected by cutting the bark and catching as 

 much as flows out at once. Dr. Riddell calculates 

 that ten average-sized plants will yield as nmch 

 juice_ as will make a pound of gutta-percha substance, 

 but it is not kuowu yet how far the plant \vill bear 

 tapping without injury, nor how often, or at what 

 intervals the extractions of the juice might be made. 

 The juice extracted may either be exposed to tho 

 sun in a shallow vessel, or left to dry in the shade : 

 by the former process the substance becomes a little 

 darker than by the latter. When it has attained a 

 tough consistency it may be well worked up in very 

 hot water with a wooden kneader, or boiled ; either 

 process serves to remove an acrid property of the 

 juice, as also all other matter but the gutta-percha 

 itself. It is believed that the more it is boiled and 

 worked up, the harder it will eventually become 

 when cool. 



"Comparison with the true gutta-percha gives the 

 following results. 



"Sulphuric acid chars it. 



" Nitric acid converts it into a yellow resinous 

 substance. 



" Muriatic acid has very little effect upon it. 



"Acetic acid has no effect. 



" Alcohol, ditto. 



" Spirit of turpentine dissolves it into a viscid 

 glue, which, when taken up between the fiuger ami 

 thumb, pressed together and then separateil, shows 

 numberless minute aud .separate threads. 



"The above tests correspond exactly with the estab- 

 lished residts of the real gutta-percha. The 

 substance, however hard it may have become, becomes 

 immediately flexible in hot water, and readily takes 

 any form required, receiving and retaining impressions 

 of seals, etc., etc 



"If the madar could be profitably grown for its 

 hemp alone, it is evident, if this new substance 

 proves in practice what it now appears to be, that 

 an acre of cultivation of it would produce a large 

 (|uautity of juice, and thus materially enhance its 

 value. The poorest land sufflces for its growth, but 

 I have no doubt that if cultivated, and plentifully 

 irrigated, not ouly would the yield of juice be larger, 

 but the growth of the plant, and the fineness of its 

 fibre when made into hemp, materially increased." 



Dr. Kiddell subseijuently wrote — 



" As regards my experinu-nts with the miuldar 

 juice they are as follows; — Having collected about 

 18 fliud ounces I had it strained through a cloth, 

 and exposed 18^ ounces to solar evaporation on a 

 flat dish. In three days it became firm, separating 

 itself from the dish, and easily removed. I then 

 placed it in boiling water, and worked it well about 

 with a spatula, and when cool enough to handle, 

 kneaded it with my fingers ; when cool I fomul it 

 to weigh a little more than six ounces. I then 

 boiled it, and, as it cooled, worked it well again: 

 and on weighing the substance found it had lost one 

 ounce. I then pulled it out into shreds and boiled 

 a second time, kneading it whilst cooling, and four 

 ounces two drachms, apothecaries' weight, was obtained, 

 of what I call muildar gutta-percha. 



"The next experiment was with four Duces of the 

 juice, and placing it in a basin 1 poureil about one 

 quart of boiling water on it, stirring it up, and 

 leaving it to stand, when it broke into curds which 

 fell to the bottom. 



"I then partially poured off the fluid, .and filtered 

 the residue through paper, aud on its being sufliciently 

 dry to be removed found it to weigh one ounce 

 six drachms. It was then worked well in hot water 

 two or three times, and formed into a mass which 

 weighed six drachms, thus loosing one ounce. On 

 the whole it will be seen that the most economical 

 method of preparing the juice is by solar evaporation, 

 the residue being nearly double that of tlio second 

 experiment." 



