524 SUMMARY OF CURRENT RESEARCHES RELATING TO 



" when it is remembered that the sea-worm eats through stone and 

 " shells, and that even tobacco-leaves are bored by creatures which 

 " feed on them and dwell in them. That these odd beings can get 

 " nourishment from a bath-brick or a cornice cannot be imagined ; but 

 " if they really inhabit our walls, as is said, one more proof is given 

 " of the ubiquity and wonderful variety of life." 



BOTANY. 



A. GENERAL, including Embryology and Histology 

 of the Phanerogamia. 



Continuity of Protoplasm through the Walls of Cells.* — The 

 existence of an open communication between certain cells of the 

 hir'her plants, viz. between the different elements which make up the 

 sieve-tubes, has been shown by the recent investigations of Wilhelm, 

 Janczewski, Eussow, Tangl, Frommann, Strasburger, and others,t 

 and most emphatically by the observations of Gardiner + on the 

 pulvinus of Mimosa. W. Hillhouse adds a fresh series of observations 

 to the same effect carried on in Prof. Strasburger's laboratory at Bonn. 

 The preparations were made from the cortical tissue of the young 

 stem of the laburnum, and from the cortex and base of the leaf of a 

 number of other trees and shrubs, the best results being obtained in 

 January. 



The method pursued with the most successful results was as 

 follow^s. Kadial and tangential sections as thin as possible were pre- 

 pared, either from fresh material with a razor covered with a layer of 

 absolute alcohol, or from material which had lain some days in abso- 

 lute alcohol. The sections were then treated with dilute, and, after 

 some minutes, with concentrated sulphuric acid, which had been pro- 

 tected from the air for from 20 to 48 hours. The acid was then care- 

 fully removed by a pipette, and the preparation washed several times 

 with distilled water ; it was then inclosed in glycerin without having 

 been once removed from the glass slide. By this means the whole of 

 the cell-wall is removed ; the intercellular substance often completely 

 disappearing also. 



The author describes in detail the preparation obtained in this 

 way from a radial section through the base of the leaf of Prunus 

 laurocerasus, where the parenchyma consists almost entirely of collen- 

 chymatous cells abundantly pitted. The connection of the proto- 

 plasmic strings of adjacent cells was here distinctly seen after the 

 removal of the cell-wall. Similar results w ere obtained with a number 

 of other plants, a very good example being furnished by the winter- 

 buds of the sycamore. The protoplasmic threads which penetrate the 

 cell-walls are, however, so delicate, so refringent, and appear to be so 



* But. Centralbl., xiv. (1883) pp. 89-94, 121-4 (1 pi.), 

 t See this Journal, i. (1881) p. 70. 

 i Ibid., ante, p. 225. 



