The ideas of Du Bois-Reymond's Innitarcalcul are of great and
growing importance in all branches of the theory of functions. With
the particular system of notation that he invented, it is, no doubt, quite
possible to dispense; but it can hardly be denied that the notation is
exceedingly useful, being clear, concise, and expressive in a very high
degree. In any case Du Bois-Reymond was a mathematician of such
power and originality that it would be a great pity if so much of his
best work were allowed to be forgotten...