ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 255 



surround themselves with new strongly laminated cell-walls, grow greatly 

 in length, take up the most various and abnormal forms, and divide in the 

 ordinary way. The CEdogonium-cella form in this solution also new 

 laminated membranes, scarcely increase in length, and divide, not in the 

 ordinary way, but in that of Cladophora. These phenomena take place 

 only in cane-sugar, grape-sugar, milk-sugar, and mannite, light being 

 necessary to them. If Zygnema is placed in 10 per cent, glucose in the 

 dark, it does not grow in length, and forms no new cell-walls ; but the 

 protoplasts remain alive for some weeks, till they gradually die of want of 

 nutriment. 



When elongated Zygnema-cells are plasmolysed, the protoplast breaks 

 into two halves, one of which contains the single nucleus, the other having 

 none. Only the portions of the cells which contain the nucleus form 

 membranes, grow in length, and regenerate the entire cells; the parts 

 which contain no nucleus have not the power of forming a cell-wall or of 

 growing in length, but they may retain their life for a long while, increase 

 in volume, and form starch. 



Separation of Silver by active Albumin.* — Dr. T. Bokorny, referring 

 to the observations of Loew and himself,t that living protoplasm blackens 

 in a very dilute alkaline silver solution while dead protoplasm does not, 

 replies to the explanation offered by Hoppe-Seyler that this is due to the 

 presence in living organs of hydrogen peroxide (H2O2). If the least trace 

 (1 part in 100,000) of H2O2 were present in the living cell, suflacient iodine 

 would be set free from potassium iodide with a very dilute solution of iron 

 sulphate to produce a sensible reaction with starch. Bokorny found, 

 however, that this was not the case with Spirogyra-cells containing 

 abundance of starch-grains, while the starch-grains imbedded in the 

 protoplasm at once became blue if treated with a solution of H2O2 in the 

 presence of the same reagents. In living Spirogyra-cells saturated with 

 H2O2, and laid in a very dilute silver solution, the protoplasm rapidly 

 blackened, while the cell-walls and cell-sap remained perfectly colourless, 

 while dead Spirogyra-cells showed no reduction of silver whatever. The 

 author concludes that the reducing property depends on the presence in 

 living cells of a body (active albumin), which passes over on the death of 

 the cell into a body not possessing this property. He found that the 

 eflfect of II2O2 on this property of active albumin was at first to increase 

 its activity, this being subsequently followed by its complete suppression. 



(2) Other Cell-contents. 

 Crystalloids in the Cell-nucleus.|— Crystalloids as a constant inclosure 

 in the nucleus have hitherto been known only in Lathrsea squamaria, 

 Ufricularia, and Pinguicula. According to Dr. H. Leitgeb, they occur 

 also in Galtonia {Hyacintlius) candicans, especially in the epidermal cells 

 of the perianth-leaves and stamens, but also in the cells of the mesophyll, 

 in the epidermis of the flower-stalk, in the wall of the ovary, and occa- 

 sionally in other organs and tissues of the plant, but always much smaller 

 and less fully developed ; it is only in the underground parts that they 

 are not found. They have the form of prismatic rods, are seldom solitary, 

 but usually .in groups. They exhibit protein reactions, and may probably 

 be regarded as reserve-substances. In Pinguicula they are, under certain 

 circumstances, used up in the new formation of organs. In the perianth 

 leaves of Galtonia, they are absorbed some time before the death of the 



* Pringsheim's Jahrb. f. Wiss. Bot., xvii. (1886) pp. 347-58. 



t See this Journal, 1884, p. 249. J MT. Bot. Inst. Graz, i. (1886) pp. 113-22. 



