CHAP, i.] OF THE BROWNIAN MOVEMENTS. 341 



oscillation, with an alteration in position of from four to five 

 times their diameter. It is difficult to attribute to simple liquid 

 currents, as has often been done, these movements, which seem 

 rather due to phenomena of attraction at a short distance, and 

 must be brought back to the domain of capillarity. Now almost 

 similar movements are also observed in certain organic sub- 

 stances. Thus, when leucocytes or infusoria are disaggregated, 

 they resolve themselves into granulations animated with very 

 lively Brownian movements. Must we consider these move- 

 ments as organic or inorganic? "We scarcely know; and the 

 distinction becomes still more embarrassing with regard to the 

 movements of the pollinical favilla, of which we have already 

 said a few words. 



A number of observers, Needham, Amici, Guillemin, &c., &c., 

 have occupied themselves with the movements of the favilla, or 

 rather of its corpuscles. The last of the observers whom we 

 have just named has even attempted to compare them with the 

 movements of the spermatic animalcules. Robert Brown had 

 already observed these movements, and he had also seen them 

 in pollinical particles, especially in the ovoid and transparent 

 particles of the pollen of gramineous plants. These movements 

 have even a singular persistency, since R. Brown said that he 

 found them still in particles of pollen preserved in a herb- 

 arium for twenty- five years. Moreover, Alex. Brongniart has 

 noticed some interesting peculiarities regarding them. In one 

 case, particles of pollen having burst in water, the granulations 

 of the favilla of the pepo were still animated with their ordinary 

 oscillatory movements, and were displaced. The pollinical 

 granulations of several other species (hibiscus palustris and 

 syriacus, rosa bractea, &c.), curved inwards and changed their 

 form. 



Doubtless, there is nothing organic in the Brownian move- 

 ments of mineral particles, but they are nearly similar to the 

 Brownian movements of the debris of white globules, and of 

 disaggregated infusoria, and these last resemble the oscillations 



