CHAPTER XXXIII 



ALTERNATING GENERATION 



As we have previously observed, we cannot define analyti- 

 cally the colloid state of living substances ; and yet we can 

 verify the importance of variations in this colloid state, 

 particularly in histological differentiation. In every verte- 

 brate animal, for example, we have for protoplasm the muscle 

 state, the nerve state, the bone state, the epithelium state : 

 these various tissue states correspond for so large a group 

 as the vertebrates, and their number is considerable. 



We never observe sexual maturation in these differentiated 

 protoplasms, but we are obliged to say that, since bipolarity 

 effectively exists in all the constituent elements of these 

 various protoplasms, there must be in each type of the colloid 

 state variations corresponding to modifications in bipolarity. 

 An explanation may be taken from a hypothetical concrete 

 example. 



The two poles of one and the same bipolar element attract 

 each other ; but they are likewise in relation of attraction, 

 or at least of cohesion, with the neighbouring elements. 

 I suppose two states of equilibrium to be possible : one in 

 which the two poles of each bipolar element touch, having 

 come by attraction into contact with each other ; the other 

 in which, under the influence of surrounding actions, the 

 two poles of each bipolar element remain separated from 

 each other as if by a tense spring. We may call one of 



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