676 GEOFFREY LAPAGE 



(1) Were these rounded bodies in my cultures individuals which 

 had rounded off ? and (2) Were these rounded bodies the same 

 as the spheres which had been seen inside the amoebae, and had 

 the amoebae been extruding them into the culture ? 



In order to throw some light on these questions a series of 

 amoebae containing spheres was kept under observation, and 

 the fact was established that the spheres were actually extruded 

 by the amoeba very frequently. Text-fig. a gives the successive 

 stages in the process. It is a composite hgure drawn from 

 numbers of sketches made during observations on the living 

 object, and it shows that the extrusion of the spheres resembles 

 ordinary defaecation of the undigested remains of food. It 

 should be noted, however, that the ingested sphere was often 

 carried about in the amoeba for a considerable time, and 

 might often remain for some time in the posterior end of the 

 amoeba, separated from the water only by a very thin layer of 

 ectoplasm, giving the impression that it is about to be extruded. 

 Frequently, however, the protoplasm flowed round it again, 

 and it was taken once more into the central part of the endo- 

 plasm. Further, when a vacuole containing a sphere was lying 

 near the surface of the amoeba, and an ordinary food vacuole 

 was lying close against it, the two being separated only by 

 a thin film of protoplasm, the food vacuole might discharge its 

 contents, while the sphere remained unaffected and might be 

 taken again into the depths of the endoplasm (Text -fig. a, 8). 



There was, therefore, no external appearance which could 

 be taken as an invariable sign that the ingested body was 

 about to be extruded. A sphere might be carried about thus, 

 on the verge, as it were, of extrusion, for a long time, and might 

 then be taken in again ; or it might be suddenly extruded : 

 or it might, when deep in the endoplasm, rapidly approach 

 the surface and be extruded almost immediately after it had 

 arrived there. In one case the process lasted, from the first 

 rupture of the enclosing membrane to the time when the sphere 

 was quite free, about thirty seconds, from which it will be 

 realized that, when once the extrusion had begun, it proceeded 

 rapidly. Further, although the extrusion usually took place 



