Sept. 1, 1902.] THE TROPICAL 
AGRICUJ.rURIST. 
Hi 
I The interest to us lies «ot so much in this aa in 
bia indication of the preseuoe in the tissues of gutta 
peroba. The discovery he made known in the follow- 
ing words ; — 
' The most singular feature about the pJant ia 
the extraordinary abundance of an elastic gum in 
all the younger tissues — excepting perhaps the wood 
proper, — in the bark (in the u:nal sense of the wiu'd), 
the leaves and petioles, and pericarp ; any of these, 
snapped across, and the parts drawn asundev, exhibit 
thvi silvery sheen of innumerable threads otthisgnm." 
His acoonnt continues : " The morphological re- 
lations and general histology of the cells which give 
rise to the substance, we hope to have the op- 
portunity of describing from specimens in fluid or 
living, which, through Dr. Henry's kind offices, there 
is proimbility we may soon receive." 
When the promise I specimens arrived Mr. (now 
Prof.) E. E. Weiss undertook the examination of 
them, and from the account of his investigations, 
published in the Transaction of the Linnean Socifty 
(Series 2, Botany, iii., p. 2}3j, the following sentences 
are drawn : — 
The threads of Eucommia consist of caoutchouc, for 
they are insoluble in alcohol, acids and alkalis, 
though they become soft when treated with ammo- 
Xnia. They dissolve in chloroform and turpentine, 
and swell up in ether. When heated they melt, 
and they burn with the characteristic smell of 
burning rubber. 
From the bark the rubber can very readily be 
extra^'ted. If the bark be broken in pieces and 
pounded in a mortar, the mass can be roughly 
separated into two parts, one consisting of the tangled 
elastic threads, with small bits of broken bark adher- 
ing to them, the other chiefly of bits of bark con- 
taining, no doubt, smaller pieces of the threads. Prom 
both parts ohlorofom will dissolve out caoutchouc, 
a larger amount naturally from the portion which 
consists chiefly of the threads. Thug, a sample of 
the threads and hark weighing 443 nig. gave as 
much as 2.5 mg. of caoutchouc, while the remaining 
bark, weighing 607 mg,, yielded only 6 mg. Taking 
the two quantities together, the yield of caoutchouc 
was 3 per cent, of the weight of the dry bark, and 
-the same iisriire was arrived at independently by 
.Prof. P. W. Oliver witli another sample. The 
threads are clear and homogenous, and the only im- 
purity in the chloroform extract seems to be a 
little resin, which can be washed out with alcohol. 
Whether: the bark can be made use of commercially 
T must leave to those who are more experienced in 
technical matters. The distribution of the caout- 
chouc-containing cells I had been able to determine 
from the dry material which I first examined, and 
these observations were confirmed by the esamina- 
tion of the material preserved in alcohol. They occur 
in the inner portions of the cortex, very much in 
the position in which the latex cells of Euphorbia 
are found, but are even more frequent in the 
Becondary phloem, where they run between the 
companion cells, and in both cases present the ap- 
pearance of very long narrow cells, attaining such 
a length that one only occasionally finds their ends. 
In the leaf a group of caoutchouc containing cells 
accompanies the ramifying fibro-vascular bundles, rnnn- 
ing just below the phloem, while in the petiole and 
all along the bundle of the midrib they form two 
groups at the sides of the bundle, and do not run 
below it. The pericarp of Eucommia, which re- 
sembles in appearance that of the elmn is especially 
rich in these caoutchouc-containing cells. Below the 
epidermis we find a few layers of large chlorophyll- 
containing cortical cells, which become very much 
compressed in the dry fruit. Within these are the 
fibro-vascular bundles, the main trunks running longi- 
tudinally, and connected by branching and anastomos- 
ing leaser bundles. The longitudinal bundles have 
ft Btrong group of caoutchonc coutaining cells accom- 
panying them on their inner aide, and immediately 
ioneath fUem we find a large ma^s of circularly 
running cells of the same nature, forming quite a 
dense coat of hvpbse-like thin-walled celiv, st.iowing 
their cell-walls very distinctly wlien the c!\ortti;houc ba-i 
been dissolved out by chloroform." 
These investitiations did not settle the position of 
the genus, and Mr. Weiss left the matter with the 
remark that perhaps the tribe CtotcnEse might includ.j 
Eucommia in preference to Phjllgntbse of the s.-mo 
order — Bnphoi biacese. ■ • 
Since these first researches, .rhade on imperfect 
material, further knowledge has been dr.e to the kdc- 
ce.ss of scientific and horlicuUiirAl establishments in 
Palis in obtaining first dried flowering specimens' 
and now living plants. From the museum of the 
Jardin des Plantea came the material wh<-reby Prof. 
Oliver v/as enabled to publish a second figure 
(Hooker' s Icones plantarum, t. 2361) and Dr. Solereder'a 
researches (Brrichtc der Dciitscken boio.nischen Gesel- 
Ischoft, xvii, 1699, p. 387) were made upon flowers sent 
to him from Paris and fruits supplied from Kew ; while 
the living plants in cul ivalioc at the Jti.rdin Colonial 
in the garden of the Faculty of Medicine, and by 
the firm of Vilmorin, Andiieux, & Co., have sup- 
plied material for the anatomical investigations of 
M. Barthelat (Journal de Bofanique, xiv., 1900, p. 55J 
and the economic inquiry of ill^I. D^ bowski snd Fron 
(C'oniptes R'endua de V Acaflemie des Sciences, Paris, 
cxxix,, p. 558). 
Examination of the dried flowering specimens which 
had been received in 1894 from a French missionary 
— Pere Farges and were taken from trees lultiva ted 
in Szechuen, caused Professors Oliver and Baillot; to 
agree in placing Eucommia in the order TroAioden- 
dracesB. Solereder refers it to Ham-xmelidacese. It 
is impossible to discuss here the cause of this dif- 
ference of opinion; let it suffice to say ttiat it indi- 
cates the difficulty experienced in assigning to its 
true position this peculiar genus. Wherever from 
external morphological characters we place it, the 
allied plants are not rubber-or gutta-yielding plants. 
Solereder observes this, and compares in justifica- 
tion of his view the Hippocrateacea, in which 
caoutchouc cells are found in certain species. 
There are great differences between the caoutchouc 
cells of Eucommia and of the Euphorbiaceae. In the 
latter the whole system is one complicated network 
arising from the branching of cells which are pre- 
sent in the embryo, which grow with the growing 
plant, ramifying and uniting, so that the outflow 
of one cut vessel ia more than its contents, because 
other vssels feed it as it bleeds, lu Eucommia the 
caoutchouc vessels do not branch and unite, nor 
are they present, according to Barthelat, in the em- 
bryo. Tlieir contents, too, are more of the nature 
of gutta percha than indiarubber; and in structure 
they are much more similar to the cells which 
yield the gutta percha in Dichopsis than to the laticifer- 
ous vessels of Hevea, Manikot, Sapium, and other 
Euphorbiaceous plants. 
To Weiss' description of the anatomy Barthelat 
adds somewhat. He found that the cortical 
parenchyma of the young stem contained abundant 
cioutchouc cells, sometimes running singly, some- 
times two or three together. In the roots he found 
the same cells in the phloem, and in the petioles 
both in and below the phloem ; while in the leaf- 
blades they were very plentiful, running with the 
nerves and branching from theiu to end in a swollen 
extremity under the palisade parenchyma of the 
upper surface. 
Caoutchouc is thus seen to be present in every part 
of the plant except the wood and the outer layer of 
parenchyma of the young I'oots. 
We may now leave the anatomy of the plant to 
quote from the paper by MM. Dybowski and Fron 
of the economic possibilities which Eucouim.ia may 
possess. The following statements are translated 
from pp. 559-SCO of their paper : — 
Our attention wi\3 called to tho similar way in 
which the contents of the laticiferous vesselg of 
Palanuium and Eutommia becgmtf evident wheu {h% 
