404 SUMMARY OF CURRENT RESEARCHES RELATING TO 



by a more or less sickle-shaped body corresponding to the stah- 

 platte of Noctiluca ; the ventral shell has an anterior notch in which 

 lies the mouth-slit ; the protoplasmic contents entirely fill up the 

 space between the two shells ; there is no trace of a tentacle present. 



Another Infusorian, Pyrophacus Jiorologium, belongs to the same 

 family, and like Ptychodiscus was found by Stein in the stomach of 

 Salpa ; the body is inclosed in a shell which has the appearance of 

 being made up of a number of pieces united in a mosaic fashion ; in 

 the same way the shell is made up of a dorsal and ventral half united 

 by membrane ; the former is distinguished by the presence of a 

 stahplatte ; in addition to a mouth-opening there is another opening 

 which is analogous to an anus. 



Noctiluca miliaris, as is well known, has a great share in producing 

 phosphorescence of the sea on our own coast and elsewhere ; but in 

 the neighbourhood of Kiel this Infusorian is not to be found and the 

 phosphorescence there is chiefly due to Ceratium and Prorocentrum 

 micans. 



BOTANY. 



A. GENERAL, including Embryology and Histology of the 

 Phanerogamia. 



Continuity of Protoplasm^* — E. Eussow declares his belief that 

 in all plants during their entire life the whole of the protoplasm is 

 continuous. He bases this conclusion on a series of observations 

 carried out on a plan slightly modified from that of Hillhouse. Fresh 

 sections of the plant to be examined are laid in a solution of • 2 p.c. 

 iodine and 1 • 64 p.c. potassium iodide, to which is added a mixture of 

 3/4 sulphuric acid, and a small quantity of the same acid more concen- 

 trated. The sections are then repeatedly washed and stained by 

 anilin-blue ; before staining they are sometimes laid in picric acid. 



Tangential sections of the cortex of many plants treated in this 

 way showed very clearly the strings of protoplasm connecting adjoining 

 cells. The periphery of the cell-contents is wavy on the longitudinal 

 sides, more or less uneven on the transverse sides. The concavities, 

 which are usually rounded, correspond to the pits ; and between the 

 corresponding prolongations of two adjacent cells are seen from three 

 to five moniliform threads of protoplasm, usually strongly curved. 

 In each thread are several granules, usually at regular distances. 

 These threads are met with also between the parenchymatous cells of 

 the bast, and between these and the cells of the medullary rays ; in 

 the latter case they are extremely delicate. The threads are seen 

 especially well in Bhamnus, Fraxinus, Humulus, and Gentiana cruciata ; 

 also in the cortex of numerous other woody plants, as Prunus, 

 Quercus, Populus, Alnus, ^sculus, &c., and in some herbaceous or 

 climbing plants, such as Lunaria rediviva, Lappa, Gucurbita, &c. 



* SB. Dorpat Naturf. Gesell., 1883. See Bot. Centralbl., xvii. (1884) p. 237. 

 Cf. this Journal, iii. (1883) pp. 225, 524, 677, ante, p. 76. 



