854 
MR. W. GARDINER ON THE CONTINUITY OF THE 
of striation, which gradually becomes more and more defined until distinct threads 
can be observed. At first the diameter of the threads gradually diminishes from the 
protoplasm to the cell-wall, so that it is impossible to trace the thread over the whole 
of its course (Plate 70, fig. 40) ; but after some time it comes more clearly into view, 
until at length it is apparent that it extends right up to the wall in question. 
The thickness of the threads varies greatly. Up to a certain point, more and more 
threads come into view the longer the cell is observed, until at length the appearance 
presented will be that of a central contracted sphere of protoplasm from which radiate 
out to the cell-wall numerous fine threads, some of which are of an appreciable size, 
other smaller though still well defined, and others so difficult to see that their 
presence is only indicated by a faint striation traversing the space between the 
protoplasm and the cell-wall. 
The phenomenon of the gradual definition of the threads appears to suggest that a 
thickening of their substance has taken place, and as Bower * has observed, this in 
reality does occur. 
He has seen also that the nodal swellings appear to travel from the protoplasm to 
the cell-wall, and is of opinion that the thickening of the threads is due in a great 
measure to a drawing out of fresh substance from the main protoplasmic body. He 
also suggests that lateral coalescence of the strings may occur. My view of the case, 
however, differs from his. It is certain that at first the protoplasm quickly contracts, 
owing to the rapid diffusion which occurs. The water diffuses from the cell vacuole 
into the salt-solution, much more quickly than the salt-solution diffuses into the water, 
so that the contraction of the protoplasm reaches its maximum when it has lost the 
greatest amount of water. After a time osmosis ceases, but not until the strength of 
the fluid, both inside and outside of the protoplasm, is the same. And in the 
subsequent equilibrium which occurs, the protoplasm, which had before suffered an 
abnormal contraction, owing to the rapid loss of the water it had contained ; now takes 
up in exchange a small quantity of the salt-solution, and the ultra shrinking (so to 
speak) is relieved,! and a definite swelling of the protoplasm takes place. Thus the 
tension on the threads is no longer so great, and, owing to their elastic character, they 
thicken up and are thus brought into view. Subsequently they cease to thicken, and 
by the time the shrunken protoplasm has regained its equilibrium they become quite 
lax. Both Bower and myself have observed that, after some length of time has 
elapsed, the threads execute lateral vibrations which are possibly caused by currents 
due either to diffusion or to temperature. 
It seems probable that the action of the salt-solution, unless very dilute, causes 
grave changes to take place in the protoplasm. Ordinary cells do not give much 
evidence of this, since on washing out with water they regain their usual appearance. 
* Loc. cit. 
| It loses, in fact (if I may be allowed to use the expression), some of its water of constitution, and 
takes up in its stead the salt-solution. 
