Meyen's Report for 1839 on Physiological Botany. 333 



"crystalline moisture " or fluid in the cotyledons. He says 

 he has observed, that at certain hours in the day, as also 

 about midday, a transparent fluid of a silvery lustre is found 

 on the surface of the cotyledons, which he calls the " crystal- 

 line moisture." The drops of this fluid are so small that they 

 are only to be seen by the microscope, sometimes, however, 

 by the naked eye. These shining points are not to be con- 

 founded with those described by Saussure, nor with the glands 

 of other authors, &c, but this crystalline moisture is a liquid 

 which is found on all cotyledons, as on the species of Mesem- 

 bryanthemum, and particularly on M. crystallinum. 



The spiral tubes are destined, according to M. Casinese, to 

 allow the descent of a fluid, which, by means of the enlivening 

 action of light, is drawn by the leaves through the stomata. 

 The spiral tubes are therefore organs of respiration ; and from 

 the meeting of the saps of these descending and other ascend- 

 ing vessels which takes place in the leaves, a chemical process 

 ensues, L e. the oxygenized part or oxygen becomes free, and 

 makes its appearance on the transparent silvery epidermis, 

 and this is the " crystalline moisture "II M. Casinese says 

 a great deal concerning this moisture, as also about the func- 

 tions of the different elementary organs of vegetables ; how- 

 ever, it is evident that he has commenced his study of vege^ 

 table anatomy by the help of some old, and, at the same time, 

 very bad books; among the writings tof later authors, those of 

 Turpin seem to have interested him most, and he therefore 

 calls him " The Immortal." 



M. Fr. Gobel* has given a very valuable chemical ex- 

 amination of the principal Halophytes of the Caspian steppe 

 with regard to the quantity of potash and soda they contain : 

 the research was undertaken, partly in order to learn whether 

 the quantities of potash and soda vary with the age of the 

 plants, and partly to settle the question whether plants are 

 capable of converting the one alkali into the other. The prin- 

 cipal results are as follows : — 



The young plants give a much larger quantity of impure 

 soda than the old fully developed ones, but the substances so- 

 luble in water contained in the rough soda do not differ much 

 from one another in quantity. 



In the case of Halimocnemis crassifolia it appears that du- 

 ring growth a part of the chloride of sodium is converted 

 into carbonate and sulphate of soda, as is seen by analysis. 

 The young plants of Salsola clavifolia contain no chloride of 



* Reise in die Steppen des siidlielien Russlands, von Gobel, Claus und 

 Bergmann. Dorpat, 1838. 4to. Zweiter Theil, p. 108 — 138. 



