One important point cannot be too strongly insisted upon. Numerous as our documents are, they do not form a continuous series. One collection is chiefly composed of temple archives, another comes from a family deed-chest, where only such documents were preserved as were of value to the persons who collected them. At one period we may have a great number of documents relating to one sort of transaction. In the next period we may have hardly any reference to similar transactions, but very complete evidence regarding other matters. We may assume that, in such a conservative country as Assyria or Babylonia, things went on for ages in much the same way. Conclusions rightly drawn for early times are probably true for the later periods also. As far as we can test this assumption, it holds good. We may even assume that the converse is true, but that is more doubtful. Thus, we find that the practice of taking a pledge as security for debt is fully established for later times and we may therefore hesitate to deny its existence in early periods, although we have no direct evidence on the point. This absence of evidence may be due to the nature of the early collections. It may be an accident. It may also be due to the fact that the tablet acknowledging a loan was usually broken up on the return of the sum. But it might also be the fact that pledges were not usual in early times. Such was, indeed, formerly the conclusion drawn from the absence of documents referring to pledges; but Dr. B. Meissner pointed out that the legal phrase-books bore witness to the existence of the custom. The discovery of the Code of Ḥammurabi has shown that the practice not only existed, but was regulated by statute in his time. Hence the argument from silence is once more shown to be fallacious. On the other hand, it is well to avoid a dogmatic statement of the existence of a practice before the date at which we have direct evidence of it: thus, it has been stated that the tithe was paid in Babylonia “from time immemorial.” The only direct evidence comes from the time of Nebuchadrezzar II. and later. In view of such an early antiquity as that, the use of the phrase “time immemorial” was perhaps once justified. But we are now equipped with documentary evidence concerning customs two or three thousand years earlier. Until we can discover some direct evidence there of tithe, we must content ourselves with saying that it was regularly paid under the Second Empire of Babylonia. We may be firmly convinced that a custom so widespread did not spring into being all at once. But the tithe may have been a composition for earlier dues, and as such may have been introduced from Chaldea by Nabopolassar. It may therefore not have been of native Babylonian growth. In this and many similar cases it is well not to go beyond the evidence.