Les Musées d'Europe  

"M. Viardot has had the advantage of visiting all the great picture galleries of Europe, and writing his criticisms with the paintings before his eyes. That he may have sometimes erred in judgment is probable ; that he has taken great pains to examine the best pictures is certain, and that he has given us his honest convictions is quite evident. If his enthusiasm has now and then led him to speak of a painting in exaggerated terms of praise, it is hoped that his raptures may be forgiven ."--A Brief History of the Painters of All Schools (1877) by various authors