Dr. Wallich on the Amoebae. 22iJ 



without interruption to act upon it ; whilst the consolidation 

 referred to is greater at the immediate surface, and gradually 

 diminishes in extent, and finally fades away from thence 

 inwards ... In the nearly quiescent condition of Amoeba, 

 when the outline becomes more or less spherical, the greater 

 amount of consolidation of the exterior layer is shown by the 

 hyaline margin hecoming broader , and the whole of the contents 

 heing^ consequently, made to recede towards the centre .... 

 If not convertible into each other as I have described, how is 

 it that an Amoeba may be lacerated so as to form two or more 

 portions, each of which immediately presents, at every portion 

 of its surface, the same appearance as existed prior to lacera- 

 tion, not necessarily by the folding together and union of the 

 torn margins, but by the immediate development of ectosarc 

 upon the torn surface ? Let the process be called instan- 

 taneous cicatrization, or what else we will, the phenomenon 

 remains the same." — Ann. & Mag. Nat. Hist. Aug. 1863, 

 pp. 129, 130. 



" The conversion of endosarc into ectosarc, I regard as 

 analogous in its character, if not identical, with coagulation, 

 the effect produced by the mere contact of sarcode with the 

 medium in which it resides, while the converse process cotisti- 

 tutes an inherent vital function of the animal protoplasm. 

 Should this view be admissible, we have presented to us a 

 phenomenon bearing in the most important manner on the 

 general question of development, and one which, I venture to 

 affirm, is far more largely engaged in the production of specific 

 type, not only amongst the lower, but also the higher orders 

 of being, than we have heretofore been disposed to allow. I 

 allude to the reciprocal action of physical and vital forces." — 

 Ann. & Mag, Nat. Hist. Aug. 1863, pp. 147, 148. 



" I am more than ever convinced that this " (the pseudo- 

 cyclosis in Amceha) " is not a vital act, but a secondary, and 

 merely a mechanical effect consequent on the inherent vital 

 contractility of sarcode. It is only necessary to watch a 

 specimen of Amoeba carefully, to become convinced that the 

 appearance of a returning, as well as an advancing, stream of 

 granules is illusory. The stream, it will be observed, is in- 

 variably in the direction of the preponderating pseudopodial 

 projections. The particles simply flow along with the ad- 

 vancing rush of granules. There is no return stream, but the 

 semblance of one is engendered by one layer of particles remain- 

 ing at rest ivhile another is flowing past them. In short, the 

 effect is similar to that which would be produced were a 

 transparent bladder or sac of caoutchouc, containing granular 

 bodies of greater specific gravity than the viscid fluid within 

 which they are suspended, to be rolled along a plane surface. 



16* 



