292 



NA TURE 



\jfan. 29, i< 



in many plants, and later Terletzki J gave some details. 

 The observations of these authors established the occur- 

 rence of protoplasm between the parenchyma cells in a 

 small number of plants, but as I have stated this is not 

 a rare phenomenon, but one of general occurrence, and I 

 have found that the intercellular spaces of the true prosen- 

 chymatic tissues may also contain protoplasm. 



I have investigated the plasma of the intercellular 

 spaces in various collenchymatic, parenchymatic, and 

 prosenchymatic tissues. For the investigation it is very 

 important to use the reagents (absolute alcohol, picric 

 acid, or osmic acid) very shortly before cutting the sec- 

 tions. Between the larenchyma cells, in the intercellular 

 spaces protoplasm will always be found (bark and medul- 

 lary parenchyma of the Loranthacea?, Gingko, &c). In 

 longitudinal sections made of thick (2i cm.) branches of 

 Viscum the connection between the medullary parenchyma 

 cells and the protoplasm filling the intercellular spaces 

 is also clearly to be seen. On the contrary, between 

 the thin-walled cells which contain little protoplasm the 

 intercellular plasm cannot, or in very rare instances, be 

 detected (medulla of Phaseolus, Cucurbita, Sambucus, 

 &c). In the prosenchymatous tissues,^, in the bast-fibre 

 of Viscum — after moderate swelling with sulphuric acid — 

 the intercellular protoplasm, when stained with eosine, is 

 clearly to be observed. The connection of this inter- 

 cellular protoplasm with the protoplasts of the fibres is 

 easily seen. We find intercellular protoplasm also in the 

 xylem, e.g. in Rhus cotinus. 



Most important is a fact which I have discovered in the 

 course of my investigations, namely, the occurrence of 

 inter-lamellar protoplasm. This was present very con- 

 stantly in the leaves of mistletoe. The sections pre- 

 pared with dilute sulphuric acid and stained, very exactly 

 showed the fine plasmatic threads, corresponding in their 

 disposition exactly to the middle lamella. This middle- 

 lamellary " protoplasm" surrounded the protoplasts as a 

 frame the picture, and ended in the protoplasm of the 

 intercellular spaces. The threads are thicker at these 

 points. The greatest precautions must be taken in the 

 investigation of this middle-lamellary plasma : all very 

 strong acids, &c, should be kept away from the prepared 

 sections. When the cell-wall is very vigorously swelled 

 the fine processes which bind the protoplasts together 

 appear penetrating into the plasma-frame. This plasma- 

 frame surrounds each cell, and in a section the framework 

 of lamella; occur in all planes and in all successive sec- 

 tions, and all the various constituent threads appear to 

 intersect one another at all angles ; it is consequently 

 clear that the middle-lamellar)' plasm forms a plasmatic 

 mantle round the protoplasts which is increased at each 

 edge with the pillar-form (of three to four sides) inter- 

 cellular plasm portions. 



The intercellular plasm preserves its vitality, and in 

 some instances we observe that some changes take place 

 in the intercellular spaces. The intercellular plasm may 

 be observed to cover itself with a special cell-wall ; this 

 membrane is the product of the intercellular plasm. This 

 protoplasm can transform itself into a true new cell. In 

 many cases in various tissues we have found this new mi ide 

 of cell-formation, thus in the collenchymatous tissues 

 (hypoderm of Liriodendron, Ficus, Sambucus, Solanum, 

 Cucurbita, &c), or in the xylem {Rhus cotinus), in the 

 common parenchymatous bark (Viscum, Loranthus, &c), 

 in the medulla, &c. These newly formed cells grow very 

 fast, and are only in their form and appearance different 

 from the older cells. This cell-formation is very rapid, 

 and it appears at first sight that the number of the tissue 

 elements is by these "intercellular cells" {tnterstitial- 

 celler of J. G. Agardh, 2 who has observed this meta- 

 morphosis in the Floridea;), or " between-cells " {Kbzti- 

 sejtek in Hungarian), considerably increased. A con- 

 sequence of this great and fast growth is the formation 

 1 L.c , p. 169. - Botaniska Notiser, 1S84. p. 130. 



of new "secondary" or "tertiary" intercellular spaces 

 round the newly formed or transformed cells. 



General Results. — I will now briefly conclude with a 

 statement of the general results of my investigations upon 

 the communication of the protoplasts, and upon the inter- 

 cellular and middle-lamellary plasm. 



(1) The protoplasts of all the tissues in united cells are 

 in direct connection by means of finely attenuated proto- 

 plasmic threads. 



(2) The connective threads traverse the pit-closing 

 membrane (which is of a sieve-plate structure), while in 

 unpitted cells they traverse directly the cell-wall. By 

 these threads is the communication between the con- 

 nective processes which occupy the pit-cavity from both 

 sides directly established. 1 



(3) The intercellular plasm occurs not only in the inter- 

 cellular spaces of the parenchymatic tissues, but also in 

 those of true parenchymatic tissues. 



(4) This intercellular plasm contains, in many cases, 

 chlorophyll-granules 2 (Viscum). 



(5) The intercellular plasm is in direct connection with 

 the adjacent protoplasts. 



(6) Corresponding to the middle lamella around the 

 cells, we find a plasmatic frame ; the sides of this frame 

 end in the " intercellular" plasma. This plasmatic frame 

 forms a veritable mantle round the protoplasts, and is 

 increased at each edge by an intercellular plasm portion, 

 which latter has a pillar form. 



(7) Th2 connective threads of the protoplasts traverse 

 this " middle-lamellary " plasma ; both are also connected. 



(8) The probable origin of the intercellular plasma is 

 this. During the cell-division, when the division was 

 almost ended, little cytoplasmic portions become in- 

 cluded in the young cell-wall, and it is also very probable 

 that the connective threads, in many instances, are the 

 remainder of the "nuclear connective threads," and that 

 the middle-lamellary protoplasm is the remainder of 

 the " cell-plate." All these plasma portions are by the 

 thickened cell-wall much compressed together, and there- 

 fore only visible or distinctly visible by the swelling of the 

 cell-wall. 



(9) The intercellular phsm can cover itself with a cell- 

 membrane, and in this way we find at the place of the 

 intercellular spaces veritable new cells. About these new 

 cells appears later new secondary or tertiary intercellular 

 spaces. 



(10) The protoplasm of the crystal-bearing cells (crystal 

 glands) and that of the resin-cannel cells is also in 

 communication with the adjacent cells. 



The protoplasts of the plants (composed from tissues) 

 form a higher unity, one synplast. 



COLLECTING DESMIDS 



IN his recently published " Desmids of the United 

 States " the Rev. T. Wolle gives the following direc- 

 tions for collecting Desmids : — 



The outfit need not consist of more than a nest of 

 four or five tin cans (tomato or fruit), one within the 

 other, for convenience of carriage, ten or twelve wide- 

 mouthed vials, and a small ring-net made of fine muslin 

 at the end of a rod about four feet in length. After 

 selecting what seems to be a good locality, drag the net a 

 few feet among the grasses and mosses, allow the bulk of 

 the water to drain through the muslin, and then empty 

 the residue into one of the cans ; repeat this process as 

 often as may be desirable. Ten or fifteen minutes after 

 the cans have been filled most of the surface-water may 

 be poured off, and the remainder transferred to a glass 

 vial, where the solid contents will gradually sink, and the 

 superfluous water can be again poured off, and the vessel 



1 Gardiner has also observed this fact in the plants investigated by him : 

 for this reason we give this in the first place 



2 J. G. Agardh has also observed endochrome granules in the intercellular 

 spaces of the Floridea;. See Botaniska Notiser, 1S84, p. 103. 



