48 Gardiner and I to. — On Mucilage-cells 
of our knowledge we should not think it well to attempt to 
separate too sharply the structures which we have hitherto 
regarded as merely differentiated parts of the same body, and 
we would therefore prefer to state the case thus : that whether 
the ectoplasm contributes or not to the secretory changes, yet 
in all cases a very conspicuous portion of it remains, which is 
associated also with the remains of the nucleus. 
In the special instance before us the vacuole does not persist 
for any length of time, for its cavity soon becomes obliterated ; 
in the first place, in consequence of the very voluminous 
character of the secretion, and subsequently, because of the 
disorganisation of the bounding membrane (hautschicht) which 
until then had shut off the contents of the vacuole from the 
general protoplasmic body. The secretion, as we have seen, 
is not turned out of the cell, but continually collects and 
aggregates, and its remarkable swelling properties cause it to 
become very bulky, and to take up the whole of the available 
cell-space. It would, perhaps, appear at first sight that the 
vacuole takes some definite part in the secretory changes, but 
bearing in mind the mode of first formation, and taking into 
consideration the phenomena which occur in other secretory 
cells, we are led to conclude that the secretion is strictly intra- 
protoplasmic, and that neither the vacuole nor its contents 
take any direct part in the actual secretory process 1 . 
We found that the secretion was produced as a number of 
isolated drops, and we have just explained that they are 
situated in the substance of the protoplasm. They are doubt- 
less produced as a result of katabolic change, and must be 
regarded as coming under the head of metaplasm or formed 
substance. We have described in detail the sequence of 
1 A secretion being once formed, it may of course pass either to the exterior or 
interior of the cell. We have examples of both cases in Blechnum occidentale , for 
in the mucilage-hairs some few of the drops escape into the cell-vacuole, and in 
the resin-hairs the secretion passes to the outside and appears beneath the cuticle. 
We may add here that what is true of the special substances which we are 
accustomed to regard as secretions or excretions par excellence , e. g. oil, resin, &c., 
is probably true also of many other substances, nutritive and non-nutritive, which 
occur in the cell-vacuole. 
