Mr. J. E. S. jMoore — Observations upon Amoeba. 153 



originally observed were of large size, and as I have not found 

 it in smaller broods since examined) that it possibly only 

 occurs in certain conditions of activity of the same *. 



Respecting the other bodies and granules apparent in 

 Amoebae I have a few remarks to offer. 



Exclusive of matter obviously indigestible, which is rapidly 

 extruded, it appears that the remaining granules may be 

 grouped within three categories : one, containing all those 

 fragments of undigested matter, some of whose original 

 characters remain, and two others of a totally different appear- 

 ance, viz. a second, containing all those spherical homogeneous 

 globules, usually supposed to be fat (but, as the vast ma,joiity 

 of them never blacken with osmic acid, this can hardly be the 

 case), and a third, including the so-called crystalline bodies 

 (concretions of Ray Lankester) f. 



The origin and significance of the two latter remain still 

 somewhat enigmatical. Considerable light, however, may 

 be thrown on the inter-relations of the bodies in question if an 

 active Amoeba be ruptured under the weight of the cover- 

 glass (which, if the animal be surrounded by clear water, 

 usually occurs in from ten to fifteen minutes) . If the issuing 

 matter as well as that remaining, now relieved of pressure, be 

 watched under a high power, not only are the more conspicuous 

 masses of little-digested material seen to be surrounded 

 with the usual vacuoles of ingestion, but a vast number of 

 other vacuoles make their appearance, of all sizes, down to one 

 just sufficient to include the smallest apparent concretions 

 (fig. 9). Both the spherical globules and the so-called 

 crystalline bodies are seen to occupy small vacuoles and to 

 issue with them into the surrounding water. 



During the later stages of digestion many fragments of 

 nutritious matter bear a closer and closer resemblance to these 

 globules, and it is possible to arrange complete series extend- 

 ing (i.) from the undigested food on the one hand to the 

 homogeneous spheroids on the other (figs. 4-8), and (ii.) from 

 these to the so-called crystalline bodies, which are not doubly 

 refractive (fig. 10). As Miss Greenwood has pointed out J, 

 the vacuoles about the food-material decrease up to a certain 

 point ; and they are, as she thought possible, secondarily 

 acquired. 



From these observations it seems that the food, after what 



* It is probable that a body fig-ured by Leidy in his monogTaph on the 

 Rhizopods (plate v. tig. 8) is identical with that herein referred to. 

 t Quart. Journ. Micr. Sci. vol. xix. p. 484. 

 J ' Journal of Physiology,' vol. viii. pp. 204, 283. 



Ann. & Mag. N. Hist. Ser. 6. Vol. xi. 11 



