OR, THE HOME-CULTURE OF FRESH-WATER PLANTS. 
electrical influence; of any current in tlie fluid in 
which they are placed; or of any effort to recover 
their straight position. The movements, in fact, have 
very much the appearance of being spontaneous; 
an opinion in which I am pleased to find that Cap¬ 
tain Carmichael fully concurs. The late Captain 
Carmichael devoted his attention for many years to 
the investigation of marine and fresh-water Algce, 
and his opinions upon this subject are consequently 
* entitled to the highest respect. 
“ Many of the larger Oscillatorice , if carefully 
examined, may be seen to move in various direc¬ 
tions—sometimes to the right, sometimes to the 
left, sometimes slowly, sometimes briskly. I have, 
however, never perceived in them anything like an 
effort to recover the straight position which is con¬ 
sidered natural to them. On the contrary, they 
may often he observed to bend gradually, so as to 
form a very considerable curve; return again to 
the straight position; and then bend in an opposite 
direction. They have also a progressive motion; 
and two filaments, lying side by side, may frequently 
he seen advancing in opposite directions on the field 
of a microscope. This progressive motion, in all 
probability, is effected by means of cilice , although 
I have not hitherto been able to detect them. 
43 
