What is the effect of half of the last chapter of Madame Bovary, including the last two paragraphs of the novel, being devoted to the pharmacist...

In Madame Bovary, the overall effect of devoting so much of the ending to Homais is to enhance the novel's Realism. 

Flaubert's commitment to Realism in Madame Bovaryis seen throughout the novel.  The characterization of Flaubert dissecting his heroine is best seen in the novel's ending.  There is not a glorification of Emma or a beautiful conclusion where all is unified.  He avoids Romanticism and idealism in all of its forms.  Rather, the ending...

In Madame Bovary, the overall effect of devoting so much of the ending to Homais is to enhance the novel's Realism. 

Flaubert's commitment to Realism in Madame Bovary is seen throughout the novel.  The characterization of Flaubert dissecting his heroine is best seen in the novel's ending.  There is not a glorification of Emma or a beautiful conclusion where all is unified.  He avoids Romanticism and idealism in all of its forms.  Rather, the ending of the novel has nothing to do with Emma at all.  Rather, the focus is on Charles's degradation and on how his daughter ends up having to work for a living after he dies.  At the same time, Monsieur Homais's social status rises.  He is able to achieve great things and to move up the social ladder as the Bovary name declines.  The ending where he is awarded the Legion of Honor represents his own ascension.

The effect of this Realist construction is significant.  On one hand, the reader perceives the hollow emptiness.  There is a certain anticlimactic emptiness in watching characters in a novel meet an abrupt end without any sort of dramatic resolution.  The lack of glory in such an ending underscores Flaubert's commitment to Realism, a movement that wanted to depict life as it is.  In real life, bad things happen and what makes it worse is that human beings have no choice but to move on.  There is no mourning or elaborate death scene for Emma.  She simply is "no more."  That's it. Flaubert's realism creates a chilling effect in the reader.  After spending so much time with characters, the ending makes the reader understand one true horror of life is that we are temporary creatures.  The only certainty in our lives is death.  Despite all of our hopes and dreams to create a garden, the reality that underscores our existence is that only a desert awaits.

Flaubert's realism does not stop here.  In highlighting Homais's rise, Flaubert's commitment to depicting reality in his work shows that there are times when bad people win.  Homais is an opportunist who is looking out for himself.  His desire to ascend up the social ladder is similar to Emma's. However, he is smarter.  He tapped into social causes that appealed to people and was able to use these as his means for advancement.  His embrace of "science" and "rationality" played well for him because it was socially accepted.  The effect of this rise is to affect the reader with a perception of disgust at his manipulation of success.  A chilling effect emerges because Flaubert uses Homais's rise to show a world where conformity and standardization have become dominant.  In devoting the final chapter to Homais's ascension, the effect is to a perception of despair at what lies ahead.  True to Realism, Flaubert deliberately provides nothing comforting to the reader in his ending as real life offers nothing comforting in the end.