148 Dr. G. C. Wallich on the Value of 



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 inclined to allow. I allude to the recipro- 

 cal action of physical and vital forces. 



Keeping in view, then, the proofs that have been adduced by me 

 to show, 1st, that no permanent or determinate aperture exists 

 either in the contractile vesicle, the supplementary vesicles, or 

 in the outer layer (by whatever name called) of the villous ap- 

 pendage of Amoeba; 2ndly, that, whilst the ectosarc is but a 

 more consolidated condition of the endosarc, both endosarc and 

 ectosarc are reciprocally convertible one into the other; 3rdly, 

 that no appreciable difference is traceable between the ectosarc 

 of the organism and the wall of the contractile vesicle when seen 

 in its distended state ; 4thly, that the coalescence of two distinct 

 contractile vesicles takes place without reference to the special 

 aspects in which they come into contact ; Sthly, that no vestige 

 of a permanent system of sinuses is discoverable, and that the 

 facts actually observed militate in a direct manner against the 

 possibility of its existence ; 6thly, that the non-coalescence of a 

 contractile vesicle with an ordinary vacuole, when coupled with 

 what has been advanced under heads 2 and 3, and the fact that 

 the obliteration of the extemporized aperture of the contractile 

 vesicle takes place only when it comes into immediate contact 

 with the ectosarc of the villous region, renders it extremely pro- 

 bable, if not certain, that the constitution of the wall of the one 

 is identical with the investing layer of the other, — it appears to 

 me to have been conclusively established that no determinate or 

 permanent orifice occurs either in the villous region or the wall 

 of the contractile organ *. 



If, then, no permanent orifice exists at any portion of the wall 

 of the contractile vesicle, and yet, notwithstanding, two or more 

 of these organs have the faculty of coalescing, so as to constitute 

 one vesicle, even after being so far removed from each other, and 

 so subjected to change of relative position as to preclude the 

 possibility of any bond of union such as a sinus being present, — 

 it is manifest that we can only regard the coalescence of two or 

 more vesicles as due to the gradual attenuation and ultimate 

 disruption of the wall that intervenes between them. The ap- 

 pearances are those that would ensue from this process, and not 

 such as would be likely to follow on an interchange of the con- 



* On reference to the 'Annals' for June 1863, p. 441, it will be seen 

 that I allude to the illusory appearance of an aperture in the contractile 

 vesicle, engendered by an imperfect systole of that organ. I am still of 

 opinion that this appearance is illusory, and shall reserve my views on the 

 precise mode in which the discharge of the contents of the vesicle is brought 

 about for a future occasion. 



