The bacillus of diphtheria, the Klebs-Loeffler bacillus, was first described by Klebs in 1875, and was first obtained in pure culture by Loeffler in 1884. Its isolation was a matter of great difficulty, and the work of many years, because of its association in the mouth with other species of bacteria. The following table, from Hewlett's _Manual of Bacteriology_, is a good instance of one of many practical difficulties. Out of 353 cases of diphtheria, bacteriological examination found the diphtheria-bacillus alone in 216 cases. In the remaining 137 it was associated with the following organisms:-- Streptococci 6 Staphylococci 55 Bacilli 19 Torulæ 9 Sarcinæ 6 Streptococci and micrococci 2 Micrococci and bacilli 9 Streptococci and bacilli 1 Torulæ and bacilli 1 Micrococci and sarcinæ 6 Micrococci and torulæ 4 Many forms present together 19 ---- 137 ---- In December 1890 came the news that Behring and Kitasato had at last cleared the way for the use of an antitoxin:-- "Our researches on diphtheria and on tetanus have led us to the question of immunity and cure of these two diseases; and we succeeded in curing infected animals, and in immunising healthy animals, so that they have become incapable of contracting diphtheria or tetanus." Aronsen, Sidney Martin, Escherich, Klemensiewicz, and many more, were working on the same lines; and in 1893, Behring and Kossel and Heubner published the first cases treated with antitoxin. Then, in 1894, came the Congress of Hygiene and Demography at Budapest, and Roux's triumphant account of the good results already obtained. Thus the treatment is not many years old; but, if the whole world could tabulate its results, the total number of lives saved would already be somewhere above a quarter of a million. Men found it hard at first to believe the full wonder of the discovery: the medical journals of 1895 and 1896 still contain the fossils of criticism--all the _may be_ and _must be_ of the earlier debates on the new treatment. The finest of all these fossils is embedded in the _Saturday Review_ of 2nd Feb. 1895--_It is a pity that the English Press should continue to be made the cat's-paw of a gang of foreign medical adventurers._ To get at the truth, we must reckon in thousands: take, out of a whole mass of evidence, all just alike, the reports from London, Berlin, Munich, Vienna, Strasbourg, Cairo, Boston, and New York; these to begin with. Or the following facts, cut almost at random out of the medical journals:--