PROTOPLASMIC MOVEMENT. 373 



description of the rotation of the '^ cell-sap ""^ in Characese. 

 The wide distribution of the phenomenon in vegetable cells was 

 specially demonstrated in the first third of this century through 

 the observations of Meyen (' Vallisneria, Hydrocharis/ 1827), 

 E/obert Brown {' Staminal Hairs of Tradescantia/ 1831), 

 Amici, and others. Of the highest importance was Dujar- 

 din's^ description of a shapeless contractile body-substance in 

 many lower organisms (Khizopods, Infusoria, Polyps, &c.). 

 His observations upon this substance, which he called Sar- 

 kode, and its movements are even to-day of actual importance. 

 He was the first to observe the granular streaming in the 

 pseudopodia of Rhizopods. Soon phenomena of movement 

 were discovered in the cells of higher animals which resembled 

 those of sarcode in a remarkable way (Liraax eggs, Dujardin 

 1837; Planarian eggs, v. Siebold 184^1; colourless blood- 

 corpuscles, Wharton Jones 1846; and others). Ecker^ 

 showed (1849) the connection between the various " organised " 

 (muscles, ciliary hairs) and the '' unorganised" contractile 

 substances of animals, and a year later (1850) Ferd. Cohn^ 

 expressed his opinion, and supported it with good reasons, that 

 the actively motile substance of vegetable cells, which since 

 1846 (H. von Mohl'*) has been distinguished as protoplasm 

 from cell-sap, " and the contractile substance and sarcode of 

 the zoologists, if not identical, were in the highest degree ana- 

 logous structures." 



That it was not, as had till then under the influence of the 

 older cell-theory been supposed, the cell membrane which 

 eflected the contractions of animal cells, but the so-called cell 

 contents was proved by Bonders.^ 



* Dujardin, " Observ. Nouv. sur les Cephalopodes microscop," * Bull, de 

 la Soc. des Sc. natur. de France,' No. 3, 1835 ; ' Ami. Sci. Nat.,' iii, 2nd ser,, 

 p. 812, 1835 ; Ibid. iv. p. 343, 1835 (Sarcode). 



2 Alex. Ecker, " Zur Lehre vora Bau und Leben der contractilen Substanz 

 der niedersten Thiere," ' Ztschr. f. wis. Zool.' i, pp. 218—249, 1849. 



3 F. Cohn, " Nachtrage zur Naturgeschiclite desProtococcus pluvial is," 

 ' Nova Acta Acad. Leop. Cses., &c.,' xxii, 2, p. 605, 1850. 



* H. von Mohl, " Ueber die Saftbewegung iin inneru der Zelle," ' Bot. 

 Zeitung,' p. 73, 1846. 



* E. C. Douders, " Eoim, Miscliung und Funktion der elenientaren Gewebs- 



