October i, 1891] 



NATURE 



535 



stances which possess a physical and chemical resemblance to 

 eich other. An Indian Ficus, the early source of supply, soon 

 became inadequate to furnish the quantity used in the arts even 

 when the manipulation of rubber was almost unknown. Liter 

 supplies came from Htvea of Brazil, generally known as Para 

 rubber, and from Castilloa, sometimes called Central American 

 rubber, and from Manihot Glaziovii, Ceara rubber. Not only 

 are these plants now successfully cultivated in experimental 

 gardens in the tropics, but many other rubber-yielding species 

 have been added to the list. The Landolphias are among the 

 most promising of the whole : these are the African rubbers. 

 Now in addition to these, which are the chief source of supply, 

 we have Willtighbeia, from the Malayan Peninsula, Leuconotis, 

 Chilocorpus, Alslonia, Forslcnmia, and a species of a genus 

 formerly known as Urostigma, but now united with Ficus. 

 The^e names, which have little significance as they are here pro- 

 nounced in passing, are given now merely to impress upon our 

 minds the fact that the sources of a single commercial article 

 may be exceedingly diverse. Under these circumstances search 

 is being made not only for the best varieties of these species but 

 for new species as well. 



There are few excursions in the tropics which possess greater 

 interest to a botanist who cares for the industrial aspects of 

 plants than the walks through the Gardens at Buitenzorg in Java 

 and at Singapore. At both these stations the experimental 

 gardens lie at some distance from the great Gardens which the 

 tourist is expected to visit, but the exertion well repays him for 

 all discomfort. Under the almost vertical rays of the sun, are 

 here gathered the rubber-yielding plants from different countries, 

 all growing under conditions favourable for decisions as to their 

 relative value. At Buitenzorg a well-equipped laboratory stands 

 ready to answer practical questions as to quality and composition 

 of their products, and year by year the search extends. 



I mention this, not as an isolated example of what is being 

 accomplished in commercial botany, but as a fair illustration of 

 the thoroughness with which the problems are being attacked. 

 It should be further stated that at the Garden in question 

 assiduous students of the subject are eagerly welcomed, and are 

 provided with all needed appliances for carrying on technical, 

 chemical, and pharmaceutical investigations. Therefore I am 

 justified in saying thai there is every reason for believing that in 

 the very near future new sources of our most important products 

 will be opened up, and new areas placed under successful 

 cultivation. 



At this point, attention must be called to a very modest and 

 convenient hand-book on the "Commercial Botany of the Nine- 

 teenth Century," by Mr. Jackson, of the Botanical Museum 

 attached to the Royal Gardens, Kew, which not only embodies 

 a great amount of well-arranged information relative to the new 

 useful plants, but is, at the same time, a record of the existing 

 state of things in all these departments of activity. 



VIII. Fragrant Plants. 



Another illustration of our subject might be drawn from a 

 class of plants which repays close study from a biological point 

 of view — namely, those which yield perfumes. 



In speaking of the future of our fragrant plants we must dis- 

 tinguish between those of commercial value and those of purely 

 horticultural interest. The former will be less and less cultivated 

 in proportion as synthetic chemistry by its manufacture of per- 

 fumes replaces the natural by the artificial products ; for example, 

 coumarin, vanillin, nerolin, heliotropin, and even oil of winter- 

 green. 



When, however, one has seen that the aromatic plants of 

 Australia are almost free from attacks of insects and fungi, and 

 has learned to look on the impregnating substances in some 

 cases as protective against predatory insects and small foes of all 

 kinds, and in others as fungicidal, he is tempted to ask whether 

 all the substances of marked odour which we find in certain groups 

 of plants may not play a similar r6le. 



It is a fact of great interest to the surgeon that in many plants 

 there is associated with the fragrant principle a marked antiseptic 

 or fungicidal quality ; conspicuous examples of this are afforded 

 by species of Ettcalyptus, yielding eucalyptol, Styrax, yielding 

 styrone, Thymus, yielding thymol. It is interesting to note, 

 too, that some of these most modern antiseptics were important 

 constituents in the balsamic vulneraries of the earliest surgery. 



Florists' plants and the floral fashions of the future constitute 

 an engaging subject, which we can touch only lightly. It is 

 reasonably clear that while the old favourite species will hold 



NO- I 144, VOL. 44] 



their ground in the guise of improved varieties, the ntw intro- 

 ductions will come in the shape of plants with flowering branches 

 which retain their blossoms for a somewhat long period, and 

 especially those in which the flowers precede the leaves. In 

 short, the next real fashion in our gardens is probably to be the 

 flowering shrub and flowering tree, like those which are .such 

 favourites in the country from which the Western world has 

 gladly taken the gift of the chrysanthemum. 



Twice each year, of late, a reception has been held by the 

 Emperor and Empress of Japan. The receptions are in autumn 

 and in the spring. That in the autumn, popularly known as the 

 Emperor's reception, has for its floral decorations the myriad 

 forms of the national flower, the chrysanthemum ; that which is 

 given in spring, the Empress's reception, comes when the cherry 

 blossoms are at their best. One has little idea of the wealth of 

 beauty in masses of flowering shrubs and trees, until he has 

 seen the floral displays in the Imperial Gardens and the Temple 

 grounds in Tokio. 



Conclusion. 



Lack of time renders it impossible to deal with the questions 

 which attach themselves to our main question, especially as to 

 the limits of effect which cultivation may produce. W'e cannot 

 touch the problem of inheritance of acquired peculiarities, or the 

 manner in which cultivation predisposes the plant to innumer- 

 able modifications. Two of these modifications may be 

 mentioned in passing, because they serve to exemplify the 

 practical character of our subject. 



Cultivation brings about in plants very curious morphologi- 

 cal changes. For example, in the case of a well-known vege- 

 table the number of metamorphosed type- leaves forming the 

 ovary is two, and yet under cultivation the number increases 

 irregularly until the full number of units in the type of the flower 

 is reached. Prof. Bailey, of Cornell, has called attention to some 

 further interesting changes in the tomato, but the one mentioned 

 suffices to illustrate the direction of variation which plants under 

 cultivation are apt to take. Monstrosities are very apt to occur 

 in cultivated plants, and under certain conditions may be per- 

 petuated in succeeding generations, thus widening the field from 

 which utilizable plants may be taken. 



Another case of change produced by cultivation is likewise as 

 yet wholly unexplained, although much studied — namely, the 

 mutual interaction of scion and stock in grafting, budding, and 

 the like. It is probable that a further investigation of this 

 subject may yet throw light on new possibilities in plants. 



We have now arrived at the most practical question of all, 

 namely — 



In what way can the range of commercial botany be extended ? 

 In what manner, or by what means, can the introduction of new 

 species be hastened ? 



It is possible that some of you are aware of the great amount 

 of uncoordinated work which has been done and is now in hand 

 in the direction of bringing in new plants. 



The competition between the importers of new plants is so 

 great both in the Old World and the New that a very large 

 proportion of the species which would naturally commend them- 

 selves for the use of florists, for the adornment of greenhouses, 

 or for commerical ends, have been at one time or another 

 brought before the public or are being accumulated in stock. 1 he 

 same is true, although to a less extent, with regard to useful 

 vegetables and fruit. Hardly one of those which we can suggest 

 as desirable for trial has not already been investigated in 

 Europe or this country, and reported on. The pages of our 

 chemical, pharmaceutical, medical, horticultural, agricultural 

 and trade journals, especially those of high grade, contain a 

 wealth of material of this character. 



But what is needed is this : that the promising plants should 

 be systematically investigated under exhaustive conditions. It 

 is not enough that an enthusiast here, or an amateur there, 

 should give a plant a trial under imperfectly understood con- 

 ditions, and then report success or failure. The work should 

 be thorough, and every question answered categorically, so that 

 we might be placed in possession of all the facts relative to the 

 object experimented upon. Hut such an undertaking requires 

 the cooperation of many different agencies. I shall venture to 

 mention some of these. 



In the first place. Botanic Gardens amply endowed for 

 research. The Arnold Arboretum, the Shaw Garden, and the 

 Washington Experimental Garden, are American illustrations 

 of what is needed for this purpose. University gardens have their 

 place in instruction, but cannot wisely undertake this kind of work. 



