OE, THE HOME-CULTURE OF FRESH-WATER PLANTS. 



electrical influence ; of any current in the 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 Alga, 

 and his opinions upon this suhject 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 be 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 

 be 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. 



