292 



LAMARCK, HIS LIFE AND WORK 



because the subtile ambient fluids, penetrating by the 

 aHmentary canal, and being expansive, have been able, 

 by an incessantly renewed repulsion from the centre 

 towards every point of the circumference, to give 

 rise to this radiated arrangement of pa«ts. 



" It is by this cause that, in the Radiata, the intes- 

 tinal canal, although still very imperfect, since more 

 often it has only a single opening, is yet compli- 

 cated with numerous radiating vasculiform, often ram- 

 ified, appendages. 



" It is, doubtless, also by this cause that in the 

 soft Radiates, as the medusae, etc., we observe a con- 

 stant isochronic movement, movement very probably 

 resulting from the successive intermissions between 

 the masses of subtile fluids which penetrate into the 

 interior of these animals and those of the same fluids 

 which escape from it, often being spread throughout 

 all their parts. 



" We cannot say that the isochronic movements 

 of the soft Radiates are the result of their respiration ; 

 for below the vertebrate animals nature does not 

 offer, in that of any animal, these alternate and 

 measured movements of inspiration and expiration. 

 Whatever may be the respiration of Radiates, it is 

 extremely slow, and is executed without perceptible 

 movements " (p. 200). 



Tke Influence of Circumstances on the Actions and 

 Habits of. Animals. 



It is in Chapter VII. that the views of Lamarck 

 are more fully presented than elsewhere, and we 

 therefore translate all of it as literally as possible, 

 so as to preserve the exact sense of the author. 



" We do not here have to do with a line of argu- 

 ment, but with the examination of a positive fact, 

 which is more general than is supposed, and which 



