ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 773 



Functions of the Nucleus.* — In reference to the prevalent theory that 

 all the vital properties of the cell are derived from the nucleus, Herr G. 

 Klebs has made a number of observations on living cells of Zygnema 

 plasmolysed by the action of a 16 per cent, solution of sugar. One effect 

 of the plasmolysis is to cause the contracted cell-contents to divide 

 mechanically into two halves, each including one of the two cLlorophyll- 

 bodies, while the whole of the nucleus is contained in one of the two halves. 

 If the cultivation of such a plasmolysed Zygnema-^ameni is continued, it 

 is seen that the two halves of each cell exhibit very different phenomena. 

 The protoplasmic mass which contains the nucleus surrounds itself with a 

 new cell-wall, and the single chlorophyll-body divides into two, between 

 which is the nucleus. The half-cell soon begins to grow, and becomes a 

 complete normal cell. The half-cells destitute of nuclei retain their vitality 

 in some cases for as long a period as six weeks, during which time respira- 

 tion and metastasis must necessarily go on, and starch is produced even 

 more abundantly than in the portions which contain nuclei. They have, 

 however, no power of developing a new cell-wall, and the same was the 

 case in other examples observed, as Spirogyra and CEdogonium. That this 

 power is dependent on the presence of a nucleus was shown by instances 

 in which the two halves were not completely separated, but remained con- 

 nected by a narrow isthmus, when both halves became enclosed in new cell- 

 walls. The power of increasing in length goes also along with that of 

 developing a new cell-wall. Similar results were obtained with Funaria 

 hygrometrica. 



The author concludes that the power of a cell to develope a cell-wall, 

 and that of increasing in length, are essentially connected with the presence 

 of a nucleus, while the properties of assimilation and respiration are derived 

 from some other constituent of the cell. 



C2) Other Cell-contents. 



Proteids of the Seeds of Abrus precatorius.f — Mr. S. Martin states 

 that the proteids of the seeds of Ahrus, the Indian liquorice, are important 

 physiologically, because they have been shown to be possessed of poisonous 

 properties. The method of extraction used was based on the supposition 

 that the proteids present in Abrus were similar to those in other seeds, con- 

 sisting chiefly of the globulin and albumose classes. The finely ground 

 seeds were shaken first of all with chloroform to remove the red cuticle which 

 sinks in this liquid, so that the yellow kernel-powder could be easily 

 removed, and obtained in the dry state by allowing the chloroform to 

 evaporate. The powder obtained was then extracted with 15 per cent, 

 sodium chloride solution for twenty-four hours, and the mixture filtered. 

 The yellowish filtrate was distinctly acid, and gave a copious precipitate 

 on boiling. The proteids were separated from this filtrate in two ways. 



(1) Saturation with neutral ammonium sulphate and shaking for four 

 hours throws down all the proteids in solution. (2) Saturation with 

 sodium chloride and shaking for many hours gives only a scanty pre- 

 cipitate, which becomes copious on adding a large excess of glacial acetic 

 acid. The properties of the globulin are that it is insoluble in distilled 

 water, but readily soluble in 10 to 15 per cent, sodium chloiide or mag- 

 nesium sulphate solution. It is completely precipitated from solution by 

 saturation with sodium chloride after slightly acidifying. The albumose 

 is soluble in cold or boiling distilled water. It is not precipitated from 



* Biol. Centralbl., vii. (1887) pp- 161-8, and Ber. Deutsch. Bot. Gesell., v. (1887) 

 pp. 181-8. t Proc. Roy. Soc. Lond., xlii. (1887) pp. 331-4. 



