I Shall not attempt to repeat or even to summarize the excellent discussion of glottochronology by Dr D. H. Hymes (Current Anthropology, I, I, January 1960), but shall to some extent base my remarks on it. It seems to me that glottochronology is one method of analysis among many. It sheds a certain light of its own which is most useful when related to other kinds of study. The method of common innovations, for example, gives a much more precise picture of the genetic relations of a set of languages, and it does not depend on so many controversial assumptions. But the chronology which it gives is always a relative one. Furthermore, it depends for its success on quite deep studies of the languages in question, since it is always hazardous to say that a particular form or construction is not present in a language. Further study may often reveal it. It is, of course, also true of glottochronology that it depends for its full success on the deep study of the languages under consideration and of their cognate interrelations. It appears that we shall have to wait quite some time for those conditions to be satisfied in African studies, and field workers have had to go ahead and use these methods as best they can in order to make some kind of sense out of the vast mass of data before them. It seems to me that this is legitimate if all the conclusions of such exploratory ventures are firmly held to be subject to change without notice. We can at least get some idea of the time depths with which we are dealing. Language relationships which are recent enough to be of historical interest are fairly easy to handle even with crude methods. It is with respect to the older relationships that technique is stretched to its uttermost limits. Even here glottochronology can establish a ground against which recent borrrowings, containing the traces left by historical process, can be more readily distinguished.

In this paper an attempt will be made to set out the basic facts about the blood groups and other genetical characters in so far as they apply to anthropology.

In very few regions of Africa are the blood group distributions known in detail—even for the ABO system—and the maps must therefore be treated with reserve. Small-scale maps are useful for showing general trends, such as the rise in O frequency from the Middle East to Central Africa, but they cannot do justice to the considerable local fluctuation which detailed surveys have revealed (especially in Liberia and in the Eastern Congo).

It frequently happens that the only information available on interrelationships and former movements of African peoples lies in their oral traditions and myths. In the myths it is difficult to disentangle symbolic from historical events and personalities, while, fascinating though it is to listen to an old man recounting the movements of his ‘ancestors’ countless generations earlier, one frequently wishes that there were some independent line of evidence against which his statements could be checked. Such an independent line of evidence is provided by the steadily accumulating data on the genetic Constitution of African peoples. The Nilotes provide an illustration of its usefulness, of its limitations, of the type of additional information required to extract the maximum from the data, and of the postulates necessary to do so.

Since African Political Systems, edited by Fortes and Evans-Pritchard in 1940, many monographs have been published on particular political organization of pre-colonial Africa. Some attempts have been made to synthesize these data in order to constitute a typology of African political organizations; for instance the segmentary type has been studied in Middleton's Tribes Without Rulers (1958), and the absolute monarchies have been given an important place by Murdock in his Africa (1959) and by others (e.g. P. Hadfield: Traits of Divine Kingship in Africa, London, 1949). Typological research falls within the historian's province if he is interested in the problem of uniformities in history.

Between 1959 and 1961 I worked with an Ethiopian research student, Gētāčaw Takla Māryām, on the constitutional history of Ethiopia from the Aksumite period (first to fourth centuries A.D.) to the end of the seventeenth century. So far as could be discovered, no serious attempt has yet been made to deal with this subject by means of strict documentation. The first step therefore has been to collect from printed Ethiopic material (mainly written in Ge‘ez) and from Ge‘ez manuscripts a body of documents and charters which will ultimately form the basis of a constitutional history. The aim has been to produce something like Stubbs's Select Charters, for some such basis is an essential preliminary in a field in which be one of the resultes of our study. For place-names the position is a little better, since Conti Rossini produced many years ago an index to names in material published up to 1894; and not long ago I compiled one for the historical texts published in the Corpus Scriptorum Christianorum Orientalium (CSCO).The work on constitutional history, which is still in progress, has involved the study and translation of four categories of document written in Ge'ez; these are:

(1) The early Ge'ez (and Greek) inscriptions of the Aksumite period.

(2) The Lives of the Ethiopian saints (gadla qedusān) of the sixth, thirteenth, fourteenth, fifteenth, and sixteenth centuries, including the Synaxarium (senkesār) or general collection of lives of saints.

(3) The land charters and other documents in the Book of Aksum, from the tenth to seventeenth centuries, with a few attributed to kings from the fourth to ninth centuries.

(4) The Chronicles, now mostly available in printed form, either in the CSCO, or published individually; some are to be found in periodicals.