Dr. Wallicli on the Amoebae. 225 



in the interior of Amoeba. But as soon as the action of the 

 atmosphere causes coagulation or consolidation of the tears of 

 caoutchouc, the innate contractility becomes at once manifest. 

 A precisely similar effect is produced by the contact between 

 endosarc and water. In the case of caoutchouc the consoli- 

 dation once established there is no return to the previous con- 

 dition. Why? Simpli/ because its mtality ceased with its 

 extrusion from the tree. But even here the analogy is not 

 altogether destroyed ; for the contractility " (elasticity) '^ may 

 be materially diminished by heat, and the mass may again 

 become an adhesive semifluid, capable of permanently assuming 

 any figure. Yet, on the reduction of the temperature, consoli- 

 dation again takes place, and, with it, the mass resumes its 

 elasticity. So that, assuming sarcode to be endowed with 

 vitality — a factj I presume, not admitting of denial — and also 

 that it is contractile, we have not only all the conditions that 

 place the phenomena observed in the light of simple cause and 

 effect, but it appears to me absolutely impossible to ac- 

 count for them in any other way." — Ann. & Mag. Nat. 

 Hist. Dec. 1863, pp. 455-6. 



General Remarks on the Foregoing Extracts. — Concerning 

 Dr. Gruber's "^^ Diagnosis in Amoeba " *, I have to observe, that 

 in my experience the number of nuclei may vary almost to 

 any moderate extent, in certain forms and under certain con- 

 ditions. This fact becomes very obvious when the same 

 forms are observed^ in the same localities, for several succes- 

 sive years. To say that, because multiple nuclei occur in 

 forms which present no other — or, at all events, no other 

 important — characters which distinguish them from those pos- 

 sessing only single nuclei, they are therefore different species, 

 is scarcely a legitimate conclusion. For we find it very 

 commonly negatived in toto in the case of Amoeba (as already 

 shown, ante), as well as in Arcella vulgaris and other forms. 

 When this Arcella occurs in anything like abundance, and its 

 tests are neither too old nor too obscured by dirt, we may con- 

 stantly see several distinct nuclei within the body-substance 

 of the animal. In one example I observed no less than six. 

 The following memorandum in one of my note-books relates 

 to this specimen : — " Oct. 21, 1864. Found a large Arcella 

 vulgaris, Dy-g^^- ! with nine contractile vesicles, all peripheral 

 and acting energetically, but of course not synchronously. 

 Average interval between diastole and systole, as nearly as 

 I could estimate, about four minutes. There were on this 

 specimen six distinct nuclei of the ordinary size.'''' 



Dr. Gruber^s Remarks as to Peessure being the Cause of 

 the Movement of Granular Particles &c. in the Body -substance 

 * See anth p. 220. 



