Davey, on Bryonia Dioica. 
103 
It is worthy of remark^ that protoplasm is not only the 
substance from which normal parts are formed^ but it is also 
the material by which injuries are repaired. If a portion of 
an embryonic mass be cut partially off, fresh protoplasm is 
seen to exude to restore the part^ cavities form in it^ &c., 
while the nearly detached part loses its vitality and collapses. 
Wifh respect to the manner in which protoplasm reaches 
the distal cells of a hair or a mass^ it seems to me to be most 
probable that it occurs by endosmosis from cell to cell ; that 
endosmosis takes place readily through the wall of an imma- 
ture cell is certain^ for some of the clubbed hairs can be seen 
to fill and burst when immersed in water. 
In every instance in which I have seen protoplasm escape 
into water it has displayed the tendency to ropy coagulation 
described by Mr. Wenham^ and its granules when diffused in 
water are in active motion. 
Mr. Wenham suggests that the form of embryo leaves 
may perhaps be given to them by pressure of surrounding 
and similar parts^ but in the case of the Bryony this would 
not appear to be the case, for the embryo tendrils and leaves, 
though subjected to the same mechanical support or pressure, 
seem to have, from the very first, distinctive characters. 
I must observe that, in the case of the Bryony, the transi- 
tions of protoplasm can only be observed with clearness at 
the margin of a mass ; the thickness of central parts is too 
great for such easy examination as in the Anacharis. 
The mere augmentation of bulk is best seen in the case of 
tendrils. 
The phenomena of cell-division are most clearly defined 
in the hairs : the process appears to be hastened by adding a 
very small quantity of ammonia to the water. 
I have in vain endeavoured to make out the manner in which 
spiral tubes are formed in the young parts : in most instances 
the spiral is seen to terminate abruptly, but in two instances I 
have observed that delicate striations were visible further on 
than the apparent termination of the vessel, and in every 
case there seems to me to be a straighter arrangement of the 
cells between which the spiral is about to pass, than else- 
where, so that probably a longitudinal interval between the 
cells exists, and this may become lined by a membrane upon 
which the spiral is developed; but all observations upon this 
point are rendered difficult and uncertain by the density of 
the masses between the vessel and the observer. 
My observations were made with a power of 200 diameters, 
and an achromatic condenser. 
In conclusion, I will remark that I have purposely omitted 
