INFUSORIES. 147 



necessary to enable them properly to fix them- 

 selves, somewhat analogous to those mechanical 

 contrivances by which the seeds of numerous 

 plants, as those of the dandelion and cranesbill, 

 are transported to a distance and enabled to 

 enter the soil and fix themselves in it. 



That any creature should begin life as an 

 animal and end it as a plant seems to contradict 

 the general analogy of creation, and requires 

 much stronger proofs than appear to have been 

 adduced in the present case, before it can be 

 admitted. The motions of the oscillating plants 

 are not very different from those of the stamina 

 of some, and of the leaves of others, as the 

 Hedysarum gyrans ; yet Adanson has proved 

 that the vibrations of the filaments are the same 

 both in hot and cold weather, and that the 

 aquatic species are equally sensible with the 

 terrestrial, therefore the movement can scarcely 

 be caused by the temperature. But as analo- 

 gous motions were observed by Mr. Brown in 

 spherical and other molecules obtained from 

 vegetables, it is evident that such motions do 

 not necessarily indicate an animal, but only a 

 kind of attraction and repulsion produced by an 

 uncertain cause. Another argument proves their 

 vegetable nature, these plants give out oxygen, 

 whereas if they were animals they would absorb 

 oxygen and give out azote. 



Professor Agardh illustrates his opinion just 



