Chapter XV —187— Origin of Vacuoles 



products of secretion of the cytoplasm capable of being dissolved 

 in them (phytosterol, lecithins, oils, carotinoids, etc.)- They may 

 remain scattered in the form of small inclusions in the cytoplasm, 

 or may fuse together, as in the spores of certain fungi and in the 

 adipose cells of animals, to constitute a single enormous fatty 

 globule occupying the entire cell. 



A distinction may therefore be made in the paraplasm between 

 hydrophilic inclusions (vacuoles) and hydrophobic inclusions (lip- 

 ide inclusions). 



Be that as it may, these investigations, taken all together, show- 

 that vacuoles are present in all cells, just as are the chondriosomes. 

 Although both are present, the vacuoles cannot, in any way what- 

 ever, be considered similar to the elements of the chondriome. 

 There is reason to think that they have no permanence, no indi- 

 viduality which is transmissible from generation to generation, or 

 as Parat says, "Only the group is significant, only the vacuome 

 is an entity, the expression of a cellular equilibrium, the bond in 

 metabolism, an 'aqueous phase' whose elements disappear and are 

 replaced by others." 



Digestive vacuoles:- The theory which we have just formulated 

 in regard to the significance of the vacuoles permits us to incorpo- 

 rate the vacuoles of the Myxomycetes in the vacuolar system. It is 

 known that in this group as well as in the Amoebas, there do not 

 seem to be any digestive vacuoles which take up vital dyes but 

 there are vacuoles which are distinguished from ordinary vacuoles 

 by their exogenous origin. These vacuoles arise from food particles 

 surrounded by a little water in the cytoplasmic mass. If the hy- 

 pothesis which we have formulated on the origin of vacuoles be 

 admitted, it follows that in spite of their exogenous origin, these 

 vacuoles are in the same category as the others, contrary to the 

 opinion of Volkonsky who definitely separates them under the 

 name of gastriole. 



There are other vacuoles, present in the flagellate algae which 

 are pulsating vacuoles. Their significance is still unknown. 



