40 Mr. H. J. Carter on Amoeba princeps 



of the nucleus in A. princeps before it arrives at the size just 

 mentioned. 



At this period the nucleus is not larger than a human blood- 

 globule, and the consistence of the nucleolus apparently homo- 

 geneous, that is, without granules, and composed of a fine deli- 

 cate yellowish film of semitrausparent plasma, in which state it 

 continues, with the exception of increasing in bulk, up to the 

 time when the Amoeba has attained about one-tenth of the 

 adult or maximum size, that is, about ^ jo^^ of an inch long 

 (fig.3,&c.). 



The nucleus at this time may be about 72^)0^^ ^^ ^^ inch, in 

 diameter; but it now undergoes duplicative division, which ends 

 in the production of tivo nuclei of the same description as the 

 original one, but each -p^'u-^th of an inch in diameter (tig. 3 Z» &/), 

 after which, subduplicative division appears to go on, until the 

 Amceba, in its adult condition and size, may contain upwards of 

 seventy of the kind of cells thus produced. 



At the commencement, the division of the daughter nuclei 

 does not appear to be always simultaneous ; so that there may 

 be two of -1 a'uoth of an inch in diameter present, and one of 

 twice this size, or six of -^-yV^yth of an inch in diameter, and one 

 of twice that size (fig. 5 c), indicating that the sum, if the large 

 one had been divided, would have been a multiple by two. But 

 however regular this may be at the commencement, as the num- 

 bers increase the sums do not agree. Thus I have distinctly 

 counted upwards of 64 but much below 80, and above 32 but 

 not exceeding 45 (figs. 1 & 4) : hence the number of these cells 

 present is not always a multiple of two. Still, whatever may be 

 the cause of this, their diameter is, for the most part, constant, 

 viz. the -y-gVnth part of an inch ; being as often perhaps slightly 

 elliptical as spherical, they may thus exceed this a little in the 

 long axis ; while their number corresponds with the size of the 

 Amoeba. 



At first they are so delicate, and their capsule so undeveloped, 

 that they present the appearance of cells composed of nothing 

 but a fine, delicate, semitransparent, homogeneous plasma 

 (fig. 1 e, & /, 7n, n) ; but as they grow older, this becomes granu- 

 liferous ; and towards the adult state, there is a distinct capsule, 

 from which (on dying) the granuliferous plasma withdraws it- 

 self into an elliptical form (fig. 4 6?). All this maybe more 

 satisfactorily demonstrated by the addition of iodine, which 

 gives the granuliferous plasma a deep amber tint ; and I think, 

 in some instances, I have seen it produce a violet one in the 

 capsule, which otherwise remains transparent, uncoloured, and 

 uncollapsed. 



On no occasion have I been able to detect a nucleus in these 



