554 ORGANOLOGY. 



little circle with its point, but in such a, manner that the axes of 

 both leaflets always remain in a straight line. This motion is 

 entirely independent of light, of day and night, and is increased by 

 heat and by a more luxuriant vegetation of the whole plant. No 

 explanation can be given of this phenomenon. 



b. Not periodical. 



Such movements take place in most of the Phanerogamia, 

 with the object of transferring the pollen upon the stigma ; the 

 stamens and stigma approaching either one or the other, or both 

 changing their position. In many plants, the stamens assume again 

 a different position after they have distributed the pollen. These 

 movements can no more be explained than the others. 



216. The phenomena exhibited by the Oscillatorics, a small 

 genus of AlgcBy are very remarkable ; the species appear to consist 

 of short fibres composed of cylindrical cells united to each other, 

 which are broader than they are long, and filled with a green 

 matter and other contents, which are partly liquid and partly gra- 

 nular. The point of every fibre is somewhat contracted and 

 rounded, frequently as clear and colourless as water. As long as 

 they vegetate vigorously, these fibres exhibit a three-fold move- 

 ment an alternating slight curvature of the anterior extremity, a 

 half pendulum-like, half-elastic bending to and fro of the anterior 

 half, and a gradual advancing movement. These movements are 

 frequently observed to occur simultaneously, and often, also, sepa- 

 rately. The causes are perfectly unknown. 



The movements of the Oscillatoria have something strange, I feel 

 almost inclined to say something mysterious, about them. I will not 

 conceal my opinion, which is entirely based upon a subjective feeling, 

 that their position in the vegetable kingdom appears still doubtful to me. 

 At all events, it appears to me to indicate a very hasty judgment for any 

 one, as Meyen has done, to ridicule those who hold such an opinion. 

 Our knowledge of these organisms is very defective, and although Ehren- 

 berg refers them to plants, this is by no means a proof of their vegetable 

 nature, but rather of Ehrenberg's modest caution, a quality of which it 

 would be very desirable that Meyen should possess a little more, and 

 which would prevent him going further than exact and certain observa- 

 tions would warrant. Meyen further associates this movement with 

 those of Spirogyra, which contracts spirally, and remains so. I have 

 never observed it : I do not deny it. But when he states that the plant 

 creeps upwards on the walls of vessels in which it is kept, and that this 

 is not the case with any other Algce, he states that which is false, and 

 which can be easily disproved, for the Algce grow naturally up the sides 

 of a glass vessel, and the water they need follows them through the action 

 of capillarity. 



All other so-called Algce of the families of Bacillarice, Desmidiece, &c. 

 are, according to Ehrenberg's observations, of yet too doubtful a nature to 

 afford them a space in this work. 



* Recent investigations on these families in Great Britain have induced some 

 botanists to adopt them unreservedly into the vegetable kingdom. See Lindley, Vege- 

 table Kingdom, p. 12. 1846. Rulfs, The British Desmidica?. 1848 TRANS. 



