PHYTO-PHYSIOLOGY. 200 



sun ; hence too does the plant die, so to speak, upon the 

 very spot, if the spiral fibres within the liber be cut 

 through, but the latter left uninjured. 



1432. The liber no longer conveys any sap to the 

 divided tracheae, solely because it has lost the condition 

 to be affected by the light-polarity. On the contrary, a 

 plant does not die so soon, if the liber be cut through, 

 but the spiral vessels preserved. The spiral fibres con- 

 ditionate consequently the motion and the excitation of 

 the organic processes. 



1433. The spiral fibres are therefore, apart even from 

 their function of respiration, or rather because this is the 

 highest vegetable function, that for the plant, which the 

 nerves are for the animal. 



1434. The tracheae of plants do not ramify like the 

 nerves of animals ; but if they divide, they separate only 

 as fascicles, which have been liberated from their origin. 

 The tracheae commence too directly in the mass of cells, 

 wherever that may happen to be, and thus become 

 what governs an organ, exactly like the animal nerves. 

 Their analogy is greatest with the sympathetic nerves. 

 The tracheae, just as in the animal kingdom, are the 

 mediators, not the founders, of vegetable life. 



1435. The principle of motion must reside in the 

 tracheae, provided that higher, and not merely chemical 

 movements, occur in the plant. 



1430. These movements must and can only exist in 

 those organs which consist almost entirely of spiral 

 vessels, and thus only in the highest organs. 



1437. Such are the leaves and the corollae. Is it 

 wished to compare the corolla, apart from its sexual re- 

 lation, with an organ in animals, it can only be con- 

 trasted with the highest nervous organ. The corolla is 

 the brain of plants, that which corresponds to light, 

 but which here remains stationary upon the sexual* 

 stage. It may be said that what is sex in the plant, 

 becomes brain in the animal, or the brain is only the 

 animal sex. 



1438. The most general function of the brain is, 



