M. Miller on the Development of Chava. 329 
branches and the shoots soon formed strong membranes.| The 
primordial utricle also follows this course until it is completely 
drawn in. This also agrees with Mohl’s observations. We have 
some striking proofs of it in the preparations of Pl. VII. figs. 21, 
22, 23, 24 and 26. In fig. 21 the preparation was treated 
with iodine, and the primordial utricle has become retracted from 
the walls of the cells; but it is not completely separated, for it 
is distinctly seen under the microscope to pass through both of 
the cells. The part which was not contracted appeared much 
More transparent and clear than the other portions. In Pl. VII. 
fig. 22 the apex is sliced longitudinally, and it is distinctly seen 
how the secondary membrane projects into the interior, but has not 
yet come into contact : I have observed this once only. In fig. 28 
_ the apex is seen to be entirely separated by constriction : it appears 
exactly as if it passed into the previous articulation. The same 
occurs in fig. 24. The preparation was treated with nitric acid, 
and the primordial utricle of the lower cell has separated from 
the cell-wall, so as to resemble an open utricle, into which we can 
easily see. Fig. 26 exhibits the two extremities of the primordial 
utricle so remarkably torn, and agreeing in this particular so much, 
that we cannot help believing that they must once have been con- 
nected. Moreover I have frequently perceived this form. Are we 
now authorized to conclude from these transitions that there occurs 
a division of the cells? I think we are! and I could have added 
many more sketches of preparations which are in my manuscript. 
One thing appears to me remarkable, viz. that all other parts of 
the plants are certainly formed from cytoblasts, and in this in- 
stance we have a division of already formed cells. However, I 
see no other deduction from the observations than the division of 
the cells. 
It is remarkable in the primordial utricle, that it (as in fig. 24) 
appears as completely separated as if it had been cut with a 
knife; it also seems not to be so important in these cells as in 
those formed from cytoblasts. Double septa formed from secon- 
dary membranes (one belonging to each cell) are in tolerably 
close contact and perfectly close the separate cells. Now as the 
primordial utricle is firmly attached to this, the interior of the 
cell is closed as regards the regular course of the circulation of 
the sap. And when it is completely absent in the old cells, as 
Mohl observed, this from its gradual absorption could not pro- 
duce any interruption to the cell-life. 
[To be continued. ] 
Ann. & Mag. N. Hist. Vol. xvii. 2A 
