What is significant about the use of the term "comrade" between the animals?

Highlight all instances of parallel structure. there is no longer any room for hope. if we wish to be free—if we mean to preserve inviolate those inestimable privileges for which we have been so long contending—if we mean not basely to abandon the noble struggle in which we have been so long engaged, and which we have pledged ourselves never to abandon until the glorious object of our contest shall be obtained—we must fight!