chasm between the two, and particularly if it is possible to compare them in the form in which they existed in earlier periods, this suspicion of a common origin may be raised to a practical certainty. Thus, direct comparison of Russian and German would certainly yield enough lexical and grammatical similarities to justify one in suspecting them to have diverged from a common source; the proof of such genetic relationship, however, can not be considered quite satisfactory until the oldest forms of German speech and Germanic speech generally have been compared with the oldest forms of Slavic speech and until both of these have been further compared with other forms of speech, such as Latin and Greek, that there is reason to believe they are genetically related to. When such extensive, not infrequently difficult, comparisons have been effected, complete evidence may often be obtained of what in the first instance would have been merely suspected. If all the forms of speech that can be shown to be genetically related are taken together and carefully compared among themselves, it is obvious that much information will be inferred as to their earlier undocumented history; in favorable cases much of the hypothetical form of speech from which the available forms have diverged may be reconstructed with a considerable degree of certainty or plausibility. If under the term history of English we include not only documented but such reconstructed history as has been referred to, we can say that at least in main outline it is possible to trace the development of our language back from the present day to a period antedating at any rate 1500 B.C. It is important to note that, though the English of to-day bears only a faint resemblance to the hypothetical reconstructed Indogermanic speech of say 1500 B.C., there could never have been a moment from that time to the present when the continuity of the language was broken. From our present standpoint that bygone speech of 1500 B.C. was as much English as it was Greek or Sanskrit. The history of the modern English words foot and its plural feet will illustrate both the vast difference between the two forms of speech at either end of the series and the gradual character of the changes that have taken place within the series. Without here going into the actual evidence on which the reconstructions are based, I shall merely list the various forms which each word has had in the course of its history. Starting, then, with foot—feet, and gradually going back in time, we have fūt—fīt, fōt—fēt, fōt—fḗte, fōt—fȫ́te, fōt—fȫ́ti, fōt—fōti, fōt—fṓtir, fōt—fṓtiz, fōt—fṓtis, fōt—fṓtes, fōd—fṓdes, and finally pōd—pōdes, beyond which our evidence does not allow us to go; the last forms find their reflex in Sanskrit pād—pādas.
All languages that can be shown to be genetically related, that is, to have sprung from a common source, form a historic unit to which the term linguistic stock or linguistic family is applied. If, now, we