BRITISH FRESHWATER RHIZOPODA. 



THE PROTOPLASMIC BODY. 



The fact that no distinct membranous envelope can 

 be detected in the naked protoplasts (e.g. Amoeba proteus) 

 does not nullify the assumption of their unicellular 

 nature. Auerbach asserted that such an envelope does, 

 in fact, exist ; * but his view has been rejected by 

 later observers. It was strenuously opposed by our 

 countryman Dr. Wallich, whose conclusions, published 

 in 1863, remain unrelated, f Wallich showed that 

 ectoplasm and endoplasm (terms denoting the outer 

 layer and the more fluid inner substance of the plasma- 

 body) are not " permanent portions of the protean 

 structure, but mutually convertible one into the other, 

 and that it is an essential feature of sarcode that while 

 the outer layer is, for the time being, ipso facto instantly 

 differentiated into ectosarc, the same layer reverts to 

 the condition of endosarc."J That portion of the 

 plasma-body (referring more particularly to the 

 Amcebte) which is in immediate contact with the sur- 

 rounding medium acquires a certain density, by co- 

 agulation or some process analogous thereto, whilst 

 the central mass, containing granular matter, incepted 

 food, etc., remains semi-fluid. 



The same view has more recently been expressed by 

 Prof. Ray Lankester. He maintains that ectoplasm 

 and endoplasm " are not to be understood as distinct 

 layers, but are one and the same continuous substance ; 

 what is external at one moment, becoming internal at 

 another ; no real structural difference existing between 

 them." 



G-ruber, as the result of independent observations, 

 and without reference to Wallich's view, arrived at the 

 same conclusion. He was definitely and decidedly of 



* 'Zeitschr. fur Wiss. Zool.,' vii (1856). 

 t 'Ann. and Mag. Nat. Hist.' (3) xi (1863), pp. 369, 370. 

 The terms " ectosarc " and " endosarc " are synonymous with ectoplasm 

 and endoplasm. The latter are now in more general use, 

 ' Biologischer Centralblatt,' vi (1886). 



