The discussion of some diseases is only occasionally enlivened by the emergence of new worthwhile facts. In the case of others, it would seem that, even if only a few years have passed, each new discussion wears the air of a revolution. Hodgkin's disease, at least from the pathological standpoint, is not so extraordinarily fickle and certainly does not touch either of these two extremes of variability. But it is still a fertile field of study and presents its full share of innovations and practical results. This is perhaps due to the special position it occupies between tumours and inflammatory diseases, or possibly to a lucky series of coincidences; the truth is that events have been on the move for some years now in the case of this disease. There can be no doubt that surprising progress has been made in connec- tion with Hodgkin's disease, due, one feels, to close cooperation between several branches of medical science, each of which has had occasion to make new and useful contributions. This does not, however, hide the fact that certain important matters are still not clear, in particular the cause of the disease, its essential nature and, indeed, the best method for its treatment.