4 BRITISH FRESHWATER RHIZOPODA. 
Tut Proropuasmic Bopy. 
The fact that no distinct membranous envelope can 
be detected in the naked protoplasts (e.g. Amaba 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 unrefuted.t 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 endosare.’t That portion of the 
plasma-body (referring more particularly to the 
Ameobx) 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.” 
Gruber, 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. fiir Wiss. Zool.,’ vii (1856), 
} ‘Ann. and Mag. Nat. Hist.’ (3) xi (1863), pp. 369, 370. 
t The terms “ ectosare ” and “ endosare” are synonymons with ectoplasm 
and endoplasm. The latter are now in more veneral use, 
§ ‘Biologischer Centralblatt,’ vi (1886). 
