160 PHYSIOLOGICAL CHEMISTRY. [BOOK 11. 



capsule when the upper end is wetted is accounted for by the 

 circumstance of the upp ^r end of the seta being more twisted 

 than the lower end. It does not, however, appear that the 

 mere spiral form of the fibres is the cause of the motion, as 

 this structure exists in the green setae, which are entirely 

 insusceptible of motion from the application of moisture. 

 Nor is merely the dryness of the fibres the cause, as the green 

 setae, though thoroughly dried, do not exhibit any movement. 

 But at the period of ripening the capsule is found bent 

 towards the surface of the earth, and although I have not 

 observed it turning round, I think it is probable that during 

 this period a further twisting of the whole seta takes place, 

 this direction being given by the already spiral form of 

 the fibres, and constituting the true cause of the motions 

 observed. This is rendered more probable by the fact that 

 the spiral form of the tissue exists even after it has been 

 macerated in water." (Annals of Natural History, vol. iv. 

 p. 361.) 



These views entirely correspond with those of M. Gaudi- 

 chaud, as will appear from the following extract from his 

 Observations on Physiological Chemistry : 



" Ainsi done nous proposerions, pour obvier aux inconve- 

 nients qui resultent de la confusion des noms et des idees, 

 d'admettre trois sortes de chimie : 



" 1. La chimie des corps inorganiques, qui n'a pas besoin 

 d'etre caracterisee ; 



" 2. La chimie des corps organises, qui est aujourd'hui si 

 riche en faits admirables, mais qui n'en est pas moins desor- 

 ganisatrice pour cela ; 



" 3. La chimie physiologique ou naturelle, qui, sous Fac- 

 tion d'une force encore inconnue, sous Faction de la vie, 

 est essentiellement organisatrice, et dont le sublime artisan, 

 les laboratoires, les appareils, les agents, les forces et les 

 combinaisons n'ont rien de commun avec ceux des autres 

 chimies. 



" C'est done vers cette chimie qu'on ne connait pas 

 encore, et dont on parle toujours, qu'il faut diriger tous 

 nos efforts, si nous voulons marcher dans la route de la verite, 

 et tenter d'arriver un jour a la connaissauce des causes 



