Some years ago I contributed an article to a Festschrift in honour of Professor Carlo Fadda of Naples, in which I examined the classifications of obligations in Justinian's Institutes, and I endeavoured to show that the peculiar divisions into groups of four that we there meet with may be traced to a desire for artificial symmetry on the part of the Editors, and were neither based on any considerations of logic nor the result of mere coincidence. This article was published in the Studi Fadda in 1906 under the title 'Artificiality in Roman Juristic Classifications,' and its conclusions, though not generally accepted, have been received with favour by some eminent Romanists who have been good enough to write to me about it.