Meyen's Report for 1839 on Physiological Botany. 329 



when cast on water, in order to prove the falsity of DeCan- 

 dolle's (' Phys. Veget.' i. p. 38.) view of this subject. M. Savi 

 says, when small pieces of the green organs of Schinus, or of 

 any other of the Terebinthacece, are thrown upon water, they 

 are seen to move quickly, and as it were backwards, for a de- 

 terminate time on a short space, and in a direction constantly 

 opposite to their fractured surface ; and at the same time is 

 obsen'ed near this fractured surface an intermittent expansion 

 of a fluid which extends over the surface of the water in fine 

 circular iridescent rings, and drives away all small bodies 

 floating on its surface. 



M. DeCandoUe supposed that the intermittent emission of 

 the volatile oil out of the leaves of that plant might be pro- 

 duced merely by some contraction of the cells containing the 

 sap, but M. Savi correctly states that the peculiar sap emitted 

 [It is a liquid resin. — Mey.'\ is, in the case of Schinus, con- 

 tained, not in cells, but in vessels. By vessels M. Savi under- 

 stands the resin-passages, which I have found to be very si- 

 milar, both in their structure and course, in Schinus and other 

 Terebinthacete, to the resin-passages of the ConifercB. They 

 are long canals which run lengthways, both in the bark of the 

 leaf-stalk and of the stem, and also in the leaflets, and now 

 and then give off branches ; in the bark particularly they are 

 of so large a size, that the efflux of the still hquid resin is 

 quite natural. 



If, says M. Savi, we examine a fine section of the bark of 

 Schinus, the peculiar vessels are seen therein as fine indefi- 

 nitely long tubes with complete thick and very transparent 

 walls [i. e. a whole layer of cells. — Mey."], in which (if by the 

 section they have not already emptied the sap wloich they 

 previously secreted and contained) the sap is seen in the form 

 of different-sized globular drops, but closely packed together, 

 which flow slowly out at the sides where the vessel has been 

 torn and where the evacuation takes place. From this one 

 may conclude : 1. That if the phtenomenon were an effect of 

 the contractility of the tissue, the action could not be ascribed 

 to the walls of the cells, because the exuded sap is con- 

 tained in vessels [Harzgangen, Aley.']. 2. That the reaction 

 against the force with which the liquid streams out of the 

 leaves is not the cause of their rapid and intermittent motion, 

 for. the exudation takes places very slowly and regularly. 

 3. That the fibres of the bark of Schinus consist of proper 

 vessels ; a fact which may serve as a confirmation of Mirbel's 

 hypothesis, viz. that the bast of plants consists of proper 

 vessels and parenchym. [I cannot ratify the above statement 

 of M. Savi. — Mey.'] 1. That the sap of these vessels in Schi- 



