TRANSLOCATION OF NUTRITIVE MATERIALS 219 
cell-sap. It must not be forgotten, however, that the cell- 
membranes are all perforated by very delicate strands of 
protoplasm which extend from one protoplast to another. 
There is here a further means of transport which no doubt 
facilitates the passage. 
We may find proofs that the pathway lies along the bast 
by experiment carried out on plants in which translocation 
is actively proceeding. If we cut a branch from a suitable 
vigorously growing tree and remove from near its free end 
a ring of tissue extending inwards through the bark and 
cortex to the cambium, and then place all the lower part in 
water or moist earth, very marked effects follow. After 
some time, perhaps a few weeks, adventitious roots will be 
put out from near its end. Those which arise below the 
missing ring will be few and of small size ; those from above 
this region will be numerous and strong, and will continue 
to elongate. Any buds that may be on the part below the 
ring will not develop, while those above it will grow 
normally or even more freely than on an uninjured branch. 
The tissue immediately above the ring will become some- 
what hypertrophied and show a decided swelling. 
. The continuance of the growth shows that the water 
supply has not been cut off, but the different behaviour of 
the parts above and below the excised tissue tells us that 
the supply of nutritive material to the latter region has 
been interfered with, and the buds and adventitious roots it 
bears gradually perish of inanition. The passage of any 
food or nutritive material across the ring has become 
impossible. 
If a similar incision is made into another branch but is 
not carried so far inwards —if, that is, the ring of tissue 
removed consists only of the structures external to the 
bast—these appearances do not accompany or follow the 
wound. Evidently in this case the translocation path has 
not been interfered with. We may safely conclude there- 
fore that the transport of elaborated products, chiefly food, 
is the principal function of the bast. 
