Among the most significant of the recent discoveries in botany, is that
respecting the continuity of the protoplasm from cell to cell, by means
of delicate threads which traverse channels through the cell walls. It
had long been known, that in the "sieve" tissues of higher plants there
was such continuity through the "sieve plates," which imperfectly
separated the contiguous cells. This may be readily seen by making
longitudinal sections of a fibro-vascular bundle of a pumpkin stem,
staining with iodine, and contracting the protoplasm by alcohol.
Carefully made specimens of the soft tissues of many plants have shown
a similar protoplasmic continuity, where it had previously been
unsuspected. Some investigators are now inclined to the opinion that
protoplasmic continuity may be of universal occurrence in plants.
* * * * *