*9Q 



NA TURE 



[Jan. 29, il 



Seek out the nests of these ants within a quarter of a mile (that 

 would be enough), light a good fire over them in winter, when 

 the inhabitants are at home, and after that there would be no 

 difficulty in gradually covering the ground with plantations. 

 The dried stems of the ubiquitous thistle, cow-dung, corn-cobs, 

 or " paja " grass, would burn out these pests. 



Arthur Nicols 



Cross-Breeding Potatoes 



\ N the interesting account of the latest successful attempt at 

 raising hybrid potatoes by crossing with different species instead 

 of, as heretofore, by varieties, it is taken for granted the new 

 production will be disease-resisting. Until, however, time has 

 tested the powers of the plant after cultivation, stimulated with 

 all the appliances the potato-growers have at their command, it 

 is lather premature to trust to this. Forty years ago I saw 

 potatoes growing from seed imported direct from South America, 

 and after three y:ars' cultivation they all went with disease 

 in the year 1848. The species I could not tell. The same 

 varieties which go off with disease in this jcountry are never 

 affected in Tasmania, Australia, or New Zealand. At present 

 the newer sorts in cultivation grow so sound and healthy that 

 champions of fine quality over all the east of Scotland are now 

 offering wholesale at three pounds for one halfpenny, and cannot 

 find buyers. The results of the experiments in crossing referred 

 to, while most interesting, will only prove beneficial if a disease- 

 resisting plant is produced having all the table qualities of the 

 old Regent, as well as its great reproductive power, which, w ith 

 its ability to resist disease, it has now lost. 



James Melvix 



43, Drumsheugh Gardens, Edinburgh, January 19 



PROTOPLASM* 



"THE fact of a direct continuity between the proto- 

 *■ plasmic contents of adjacent cells is an important 

 factor in plant histology. The history of this subject is 

 briefly as follows : — 



The individuality of the plant-cells, defended by 

 Schleiden,- was first criticised by Hofmeister,' 1 and 

 more positively and later by Sachs. 4 For Sachs and also 

 for Strasburger 5 the plant is only one cohering proto- 

 plasmic entity. Nageli e has also in a recent work sup- 

 posed that the protoplasm of each cell is in direct com- 

 munication with that of the others, by means of delicate 

 protoplasmic filaments. 



So far the theoretical side cf the question. The first 

 direct observation was made in the year 1854 by Theodor 

 Hartig, and not by Sachs as Walter Gardiner 8 states. 

 We find in Hartig's paper the following description of 

 the continuity of sieve-tubes, "Behandelt man in Wasser 

 macerirte Siebrohren mit Schwefelsaure, so erfolgt haufig 

 eine vbllige oder theihveise Trennung der beiden End- 

 flachen, in welchem Falle genau zwischen den correspon- 

 direnden Ptychodearmen sich Faden aussiehen, die durch 

 Tod dieselbe Farbung und Structur zeigen wie die 

 Ptychodearme selbst. Fig. 18 stellt einen solchen Fall 

 dar." 



After Hartig's discovery, confirmed later by Hanstein 

 and Sachs: Mohl, Nageli, De Bary, Dippel, Wilhelm, 



' " On the Continuity of Protoplasm, and on the Protoplasm of the Inter- 

 cellular Spaces and the ' Middle Lamellary ' Protoplasm, with special reference 

 to the Loranthacea: and Coniferae," by Dr Jules Schaarschmidt, /r/Vrti 1 -,/<>, rent 

 of Cryptogamic Botany and the Anatomy of Plants, Assistant at the Botanic 

 Institute and Gardens, Royal HungarianUniversity at Kolosvar. Contributed 

 by^ the author. 



Schl':iden, "Grundziige der wissenschaftlichen Botanik," i. and., 

 1842-43 



II ilineister, "Die Lehre von der Pflanzenzelle," Leipzig, 1867. 



4 Sachs, " Vorlesungen fiber Pflanzenphysiologie," p. 102, Leipzig, 1882. 



5 Strasburger, " Ueber der Bau und das Wachsthum der Zellhaute." p. 246, 

 Jena, 1882. 



6 Nageli, " Mechanisch-physiologische Theorie der Abstammungslehre," 

 p. 41, Miinchen und Leipzig, 1884. 



7 Hartig, " LTeber die Querscheidewan.de zwischen den einzelnen Gliedern 

 der Siebriihren in CitcnrUtaicpo" Botanische Zeitung, xii. col. 43, 1854. 



8 W. Gardiner, "On the Continuity of the Protoplasm through the Walls 

 of Vegetable Cells." Sachs, Arieitm des let. Irstituts in Wfirzburg, iii. 

 i p. 52, 1884. 9 Hartig, I.e., col. 4^. 



Tauczewski, Russow, &c, examined the sieve-tubes and 

 their plasmic connection. For a long time the connec- 

 tion of the sieve-tubes remained the only known fact, 

 until Bornet 1 and E. Perceval Wright 2 in 1878, J. G. 

 Agardh 3 in 1879, and Schmitz 4 in 1883 (the connective 

 filaments were seen), and further, in 1884, Th. Hick 5 and 

 Kolderup-Rosenvinge 6 published some accounts of the 

 communication between adjacent cells in the Floridese. 

 It seemed to me very probable that in the Cyanophyceae 

 alfo communications between the adjacent filament-cells 

 would be found. At least the drawings that Wille 7 gives 

 put one in mind of similar phenomena. 



After J. G. Agardh, 8 Tangl, 9 in 1 880, succeeded in proving 

 the direct communication in phanerogamous plants between 

 the endosperm cells. In the various papers of Russow, 10 

 Gardiner," and Hillhouse, 1 '- these communications are 

 stated in many cases to occur in the bast-parenchyma, 

 the phloem-ray cells of numerous plants, in various 

 pulvini, in the cells of the leaf of Dionaea, in the cells 

 of the stamens of Berberis, in a great number of endo- 

 sperm cells, and in various cortical tissues. 



Finally, Terletzki 13 gave a brief account of the plasmic 

 communication of the parenchyma-cells in the stem of some 

 ferns. I have published also myself 14 a brief account of 

 this interesting object, and described briefly the observa- 

 tions made during the summer of the past year. After 

 Terletzki's paper I was induced to publish my observa- 

 tions, with the full details. 15 The physiological significance 

 of the communication was, in the first instance, not under- 

 stood ; it was believed to be chiefly for the conduction of 

 stimulus in the sensitive organs. But, after numerous 

 observations, there was little doubt that the occurrence of 

 communications between neighbouring protoplasts is not 

 the exclusive privilege of the sensitive organs, and I further 

 claimed the universality of the communication (at least in 

 tissues) in my first paper. 111 This universal occurrence is 

 since confirmed by recent researches. 



I have in my second paper 17 given the results of my 

 investigations made on various vegetative tissues. It 

 is superfluous to say anything of the importance of the 

 methods employed in such investigations. For fixing 



1 Bornet. Vide Thuret et Bornet, "Etudes phycologiques," Paris, 1878. 



- Wright, "The Formation of the so-called Siphons, and the Development 

 of the Tetraspores in Polysiphonia," Quart, /oum Mic. Science, July 1878 ; 

 Transactions of the Royal Irish Academy, xxvii. 1879. 



3 Agardh, " Florideernes Morphologi," Stockholm Vet. Akad. Hand!., 

 xv. p. 140, 1879. 



4 Schmitz. " LTntersuehungen fiber die Befruchtung der Florideen," Sitz. 

 Ber. d. Rgl. Akad. d. Wissensch., p. 2iu, Berlin, 1883. 



5 Hick, " On Protoplasmic Continuity in the FlorideaV' /ournal of Botany, 

 xxii. p. 33, 1884- 



<5 Kolderup-Rosenvinge, " Bidrag-til Polysiphonia's Morfologi," Saertryk 

 a/Botanist Tidsskrift, xiv. p. 0, 1884, f. 10-14, 26-28, 72, 75. 



I Wille, " Ueber die Zellkerne und die Poren der Wande bei den Phyco- 

 chromaceen," Ber. d. Deutschen Botan. Geselhch , i vi p. 245, 1S83, and 

 Bidrag-til Sydamcrikas Algjtora, i.-iii., Bihang till k. Svenska Vet Akad 

 Handlinear, viii. No. 18, p. 6, 1884. 8 Agardh, I.e. 



9 Tangl, " Ueber offene Communication zwischen den Zellen des Endo- 

 sperms einiger Samen." Pringsheim /akrb /. wissensckaftl. Botanik, xii. 

 ii. p. 170, 1880. 



10 Russow, "Ueber Tupfelbildung und Inhalt der Bastparenchym und 

 Baststrahlenzelleu der Dikotylen und Gymnospermen," Siiz. Ber. Dorpater 

 Natiir/orschergesellscn., p. 350, 1882. 



II Gardiner, " On Open Communication between the cells in the pulvinus 

 of Mimosa pudica," Quart, /oiiru. Microsc. Sci., New Ser., xxii. p. 365, 



" Some Recent Researches on the Continuity of the Protoplasm through 

 the Walls of Vegetable Cells," Ibid., xxiii. p. 301, 1883. 



"On the Continuity of Protoplasm through the Walls of Vegetable Cells," 

 /'. ■ ted Roy. Soc., p. 163, 1883. 



" On the Continuity of the Protoplasm through the Walls of Vegetable 

 Cells." Sachs, Arbeiten d. Bot. Instil. Wiirzbitrg, iii. i. p 52, 1884. 



12 Hillhouse, " Einige Keobachtungen fiber den intereellularen Zusammen- 

 hang von Protoplasma," Botanisches Centralblatt, xiv. p. 86, 1883. 



■3 Terletzki, "Ueber den Zusammenhang des Protoplasmas benachbarter 

 Zellen und fiber das Vorkommen von Protoplasma in Zwischenzellraumen." 

 Ber. Deutsch. Botan. Gesellsch., ii. iv. p. 169, 1884. 



14 Schaarschmidt, "A protopl.is.tok osszekottete'senek sa sejtkozi plasma 

 elofordulasanat nehany eseterol," Maeyar Xe-ecnytani Lapok. vni. No. 84, 

 p. 17, February 1884 ; see Referate in the Botanisches Centralblatt, xviii., 

 No. 18, 1884. 



'5 Schaarschmidt, "A protoplastok osszcl- .-te'seiol e'sasejlkozi plasmardl 



kulanBs tekintettel a Loranthaceakra e's Coniferakra," Ibid., No. 87, p. 65, 

 July. 



■<■ Schaarschmidt, Botanisches Centralblatt, xviii. No. 18, 1884. 



17 Schaarschmidt. Magyar NMnytani Lapok, viii. p. 77, July 1884. 



