ZOOLOGY AND BOTANY, MICEOSCOPY, ETC. 225 



BOTANY. 



A, G-ENERAL, including- Embryology and Histology of the 

 Phanerogamia. ' 



Living and Dead Protoplasm.* — In reply to tlie statement of 

 A. Mori t that formic aldehyde is the first product of assimilation in 

 plants, O. Loew and T, Bokorny give the following additional argu- 

 ments in favour of their previous conclusions on this subject.J Volatile 

 aldehydes occur in various plants, but only in extremely small quan- 

 tities ; no trace of such a substance was found in Spirogyra or any of 

 the other plants under examination. Quantitative examination shows 

 that 100 parts of the dry substance of Spirogyra precipitate no less 

 than 47 parts of metallic silver, closely corresponding to the theoretical 

 hypothesis. The fact that the death of the cell from any cause im- 

 mediately puts an end to the silver reaction, shows that we have not 

 to do with a volatile aldehyde, but that the aldehyde reaction has the 

 most intimate connection with the living condition of the cell. Living 

 protoplasm also yields a product of oxidation with an alkaline silver 

 solution, which is not the case with dead protoplasm. The reagent 

 for aldehyde used by Mori, fuchsin-sulphuric acid, is stated by the 

 authors to be in no way reliable, since, on evaporation of the sulphuric 

 acid, rosanilin is at once produced, which is immediately taken up by 

 the protoplasm. 



L. Kraetschmar§ contends that the test employed by Loew and 

 Bokorny is valueless, because dead protoplasm also has the power of 

 reducing silver salts. To this Loew and Bokorny reply 1 1 that this 

 statement is entirely the result of inaccurate observation. They 

 further state that the silver reduction does not occur with all plants, 

 whether containing chlorophyll or not, nor under all vital conditions 

 in the same organism ; it takes place only when the chemical resist- 

 ance of the protoplasm is so high that the chemical transformation 

 does not take place instantaneously on the first attack on the cell, 

 but advances much more slowly than the J.xoi,urbance in the organiza- 

 tion of the protoplasm. 



Continuity of Protoplasm in the Motile Organs of Leaves. t — 

 W. Gardiner finds that in a very great number of cases the contracted 

 primordial utricle is connected with the cell-wall by fine strings of 

 protoplasm. In several instances he has observed that many threads 

 go to the pits, and that in two adjoining cells many threads on dif- 

 ferent sides of a common cell-wall are exactly opposite to one another. 

 When saturated salt solution is added, some of the threads may give 

 way, each free end contracting, one to the main mass, and the other 



* Naturforscher, xv. (1882) p. 403 ; also Bot. Ztg., xl. (1882) pp. 832-5. 



t See this Journal, it. (1882) p. 526. 



X Ibid., i. (1881) p. 906 ; ii. (1882) pp. 67, 361, 440, 522. 



§ Bot. Ztg., xl. (1882) pp. 675-83. 



II Ibid., pp. 827-85. 



If Proc. Roy. Soc, xxiv. (1882) pp. 272-4. 



Ser. 2.— Vol. III. Q 



