— 163 — 



stituents of plants as the cause of the movement of the juices in the 

 vegetable tissues. According to the author's theory the essential oil, by 

 affecting the surface-tension of the water, causes a movement in the plant- 

 juices containing the enzymes, or the substances in which the enzymes 

 are capable of effecting a change. This movement produces enzymatic 

 reactions, in the course of which certain special bodies undergo de- 

 composition, which in turn results in an increase of osmotic pressure, 

 causing a renewed flow of water. In fact, the accumulation of water in 

 the tissues is frequently connected with enzymatic action, as the author 

 has already demonstrated on previous occasions. Not only chloroform, 

 benzene, toluene and other compounds, but also many essential oils in- 

 crease the juiciness of the tissues by allowing the water to vacate the 

 cells and by driving the plant-juice through membranes which under other 

 conditions it is unable to penetrate. Besides water certain other readily 

 hydrolysable compounds are split-off, simultaneously with enzymes, which 

 possess the power of resolving complex into simple compounds. These 

 processes again cause fresh accumulations and movements of the water. 

 Dried, compressed yeast, when exposed to the action of chloroform, eu- 

 calyptus oil, camphor oil, or camphor becomes soft within the course of 

 a few hours, and after a few days it is possible to filter the juice through 

 paper or porous porcelain. This juice contains zymase and produces al- 

 coholic fermentation in solutions of cane-sugar or glucose. Zymase is 

 more easily obtainable by this process than by the familiar methods. The 

 process may also be usefully applied in the study of the toxicity of fungi 

 and other vegetable substances. Giglioli, for instance, has tested the action 

 of 128 essential oils and other volatile bodies upon green, newly-gathered 

 cherry-laurel leaves, and has found that in almost every instance hydro- 

 cyanic acid was liberated 1 ). The author surmises that all aromatic sub- 

 stances which are generated in plants would set up a similar movement 

 of the juices in cherry-laurel leaves. According to Giglioli the part played 

 by the essential oils in the organism of the conifers consists of promoting 

 the flow of water through the cells and membranes, of acting as carriers 

 of enzymes and soluble constituents and of causing enzymatic action by 

 which the movement of the juices is favoured and increased. 



The oil content of several different plants has been determined at 

 ^uitenzorg 2 ) as follows: 50 kilos green peel of DjeroeJc dalima yielded 

 Fj cc. oil; 7,5 kilos dry buds of Gnaphalium javanicum s ) contained 3,5 cc. 



*) Similar observations on the action of volatile bodies upon plants which contain odori- 

 ferous substances in the form of glucoside-compounds have been quoted by us on previous 

 occasions. Comp. Report April 1910, 161; April 1911, 159. 



2 ) Jaarb. dep. landb. in Ned.-Indie, Batavia 1910, 50. 



3 ) Gnaphalium javaniewn, Reinw. = Antennaria javanica, D. C. (according to the Index 

 Keivensis). 



11* 



