Dec. r, 1886.] 



THE TROPICAL AGRICULTURIST, 



387 



manure for the sugar estates. [Our readers will b^ 

 reminded of poor Tytler's Sombreorum. — Ed.] 



MoNTSEEB\T. — The name of this island is perhaps 

 best known in this country in connection with lime 

 juice, althou.h the principal produce, as in most of 

 the "West Indian Islands, is sugar. The Moutserrat 

 Company exiiibts. lime juice in various forms, such 

 as cordial, bitters, sauce, etc., and also ecuelled oils 

 of limes, bergamo; and shiddock, as well as distilled 

 oil of limes and distilled oil of basil {Oci/imon sj).). 

 The ecuelled oil of limes, judging from a specimen 

 received t-ome months since, is very superior to the 

 distilled oil. Essential oils are also exhibited by 

 Mr. J. S. Hollings, consisting, in addition to those 

 nr.entioned above, of the ecuelled oil of orange (Citrus 

 Bigaradia) and the disiilled oils of Canella alba, casca- 

 rilla, lemon grass, bay (Pmenta acris) and wild basil; 

 also the pe.fumed wattrs formed during their distil- 

 lation 



British Honduras — The chief products of this 

 colony are dye wood and timber, the amount of log- 

 wood annually exported reaching 17,OuO tons. It is 

 described a< growing in immense thickets in marshy 

 places, with a crooked trunk 16 to 24 feet high, and 

 rarely thicker than a man's thigh in diameter. Two 

 varieties of the tree appear to be recognized in this 

 colony ; one having bioad leaves is considered the 

 most valuable on account of its solidity, and of yield- 

 ing a larger quantity of the dye, although the smaller- 

 leaved variety is said to yield a better quality. Of 

 fustic {Madura tinctoria) about 100 tous are annually 

 exported. The seeds of Sisamum orlenta/e "used for 

 flavouring cakes " are exhibited under the name of 

 "wangla" seeds. 



The Bah.^mas. — To pharmacists these islands are best 

 known as the geographical source of cascarilla and 

 Canella alba barks and of sponges. The exports of 

 sponge in 1885 were estimated at £oO,000. Amber- 

 gris is also found on the shore and is exported to the 

 value of £1,000 per anuum. The most marked feature 

 in Jthis Court is the fine display of sponges, which 

 will form the subject of a subsequent notice, and the 

 many beautiful treasures of 'the great deep, including 

 sea ferns, corals, sea feathers, sea star.s, sea urchins 

 and shells, etc. — Pharmaceutical Journal. 



EOOTS, 



{Coniinucil JToin p. 'dl'2.) 



A third case is conceivable — so much water might 

 be supposed to find its way in, that no air remained 

 in the interspaces between the particles of soil. Now 

 it is true that such a state of affairs is not realily 

 brought about in a normil soil; but I may iudicate 

 how the result is occasionally attained to a great 

 extent. Suppose that a layer of clay or other impene- 

 trable subsoil lies beneaoh the soil in question ; then 

 if water oozes into the soil in larger quantities than 

 can ha got rid of in the time, it is possible for 

 nearly all the air to be displaced. Of course the 

 object of good drainage is to prevent this ; and it 

 is often overlooked that drainage from below has the 

 effect of drawing in air as well as of running off 

 superfluous water — air is driven into the spaces as 

 the water leaves them. 



In speaking of the "bubbles of air" entangled in 

 the interspaces between the particles of soil, each 

 with its water-blanket, I have overlooked some details 

 as to what the bubbles really are. As a matter of 

 fact they will not remain of the same composition as 

 ordinary air, and may soon differ considerably; besides 

 the vapour of water, they may contain gases in quite 

 different proportions from those in the air outside. 

 In the type case, however, there will be some oxygen 

 present in the bubbles. 



EoOT-HAiRS.— It is not intended here to go very 

 fully into a description of the roots of land-plants ; 

 enough if you are reminded how the smaller ramific- 

 ations of a root are found to be more numerous and 

 thinner as we approach the periphery of the mass 

 of earth which they traverse. From the youngest 

 rootlets are produced the root-hairs, in enormous 

 quantities, new ones arising forwards— /.c, near the 



tip of the rootlet — as the rootlet grows on, and tho.s, 

 behind dying off after fulfilling their functions 

 These functions are chiefly to apply themselves in 

 the closest manner to the surfaces of tlie particles of 

 soil, and in this way to place the water which they 

 contain in direct continuity with the water which 

 clings with such enormous force to the surfaces of 

 the particles. Hence this water can pass from the soil 

 to the plant aud anything dissolved in the water can 

 also pass into the root-hair, and thus up into the plant, 

 I am not going to dwell on how the root-hairs them- 

 selves aid in dissolving mineral substances — corroding the 

 surfaces of the particles of soil they cling to — nor shall I 

 trouble you with the details of what substances will 

 be dissolved in the water; for, of course, you will 

 see that anything soluble will pass into solution aud 

 maj' be carried into the plant. The chief point to 

 be insisted on just now is that this water in the soil 

 will contain among other substances oxygen dis-olved 

 in it from the air-bubbles referred to above, and that 

 this dissolved o.xygen will pass into the root-hairs in 

 solution together with the minerals and any other 

 substances. This oxygen, moreover, is absolutely 

 indispensable for the life of the root-hairs ; it can 

 be easily shown that if the supply of oxygen is 

 stopped, or even diminished to any considerable extent, 

 the roots begin to die, because the root-hairs cease 

 to act. Let us look a little more closely into this 

 point. Each root-hair is a tiny cell containing living 

 protoplasm and certain other substances, all inclosed 

 in a thin, elastic, porous membrane. Now it has been 

 abuudantly proved that if such a cell is deprived of 

 oxygen, its protoplasm becomes dormant for a time, 

 an-l slowly breaks up, as it were; subsequently it 

 becomes decomposed into other and simpler materials, 

 A sort of internal combustion and fermentation take 

 place, -€ftnd these processes result in the formation 

 and liberation of bodies like carbondioxide, alcohol, 

 acetic acid, and other acid matters — substances in the 

 main not only incapable of supporting the life of the 

 root-hairs, but actually destructive of it. Evidently, 

 then, if we deprive all the root-hairs of oxygen, they 

 will eventually die. Their death will entail that of 

 the rootlets and roots to which they belong, and 

 this for two obvious reasons: — first, it is the root-hairs, 

 and the root-hairs alone which can absorb the necessary 

 water and substances in solution from the soil to 

 supply such a plant as we are concerned with; and, 

 secondly, the noxious products resulting from their 

 death accumulate in the .soil and diffuse into the 

 root, and so hasten similar decompositions in what 

 were hitherto healthy cells. It must not be supposed 

 that these disastrous consequences of tho deprivation 

 of oxygen always follow immediately. Not only are 

 the roots of some trees, for instance, able to withstand 

 ill-treatment longer than others, but, obviously, the 

 kind and degree of ill-treatment may aifect the 

 problem of how long the plant shall survive. The 

 number of rootlets and root-hairs, and the spread of 

 the roots and other factors, will obviously affect the 

 matter. Suppose the following case as an example. A 

 young tree is growing and flourishing in an open, 

 good soil, aud, for some reason or other, more soil is 

 heaped about the roots until the depth is increased 

 considerably ; the deeper situation has placed obstacles 

 in the way of the roots obtaining oxygen so readily as 

 before. Not only are the roots further from the 

 atmosphere, but the water carried down has to percolate 

 through more soil, and may part with much of its 

 oxygen (or even all) on the way: of course the 

 nature of the soil, the presence of organic matters, and 

 other circumstances, decide this. It is not at all 

 difficult to conceive of such a case where the supply 

 of oxygen to the roots is thus diminished so far 

 that the activity of the root-hairs as a whole is 

 simpl3' lovvercfl, but not destroyed, — a stage or two 

 further and they might become dormant, and their 

 protoplasm undergo intra-molecular respiration for a 

 time, and break up. It is clear that the dimini.^hed 

 activity of the roots will affect the supply of water 

 (and the substances dissolved in it") to the leavo-i : 

 this will obviously react on the tbickncs-i of the 

 annual rings, and this again ou future supplies— tine 



