What happens involving Danglars' dappled gray horses and WHY is this significant?

The Count admires Danglars' horses, thus he instructs Bertuccio to offer him the price it will take to buy them. Danglars, of course, a man of business, will sell them to the Count. Monte Cristo has his valet tell Danglars that he is engaged. Danglars thus leaves his calling card, and Monte Cristo returns the banker's visit that evening. He travels there in a carriage drawn by his newly acquired horses.

Danglars wishes to present his wife to the Count. Monsieur Debray is currently in his wife's company. The Count met Debray at the lunch at Albert de Morcerf's. Madame Danglars has thus heard of the Count from Debray (her lover) and Albert (betrothed to her daughter). Madame Danglars is astonished, however, when her maid tells her of Monte Cristo's horses. They were, earlier in the day, her horses, and now they are attached to the Count's carriage. She blames her husband, a creature of profit, for selling her prize possession. Two hours later, after his departure, Monte Cristo sends the Madame a letter and returns the horses. He even inserts a diamond on the rosettes that they wear on their ears.

The next morning when Madame de Villefort and her son take a ride in the carriage drawn by Madame Danglars' prized dappled grays, the horses become wild. They pass the Count's Auteuil residence, where Ali, the Count's valet, is conveniently located and equipped with a lasso to save the mother and son. The son has fainted. Monte Cristo pours a drop of liquid in the child's mouth, and thus the child is rejuvenated.