"Six hundred and thirty-three cases form the basis on which the report is drawn up; 549 were treated with antitoxin obtained from the laboratory of the Royal Colleges of Physicians and Surgeons; the remainder, 84 in number, were injected with antitoxin obtained from other sources. In nine instances, antitoxin from two different sources was injected into the same patient. "Statistics of the disease before the use of antitoxin are introduced as control series; these were obtained from the fever hospitals of the Metropolitan Asylums Board, and from the general hospitals; and, like the antitoxin series, are compiled from consecutive and not from selected cases. "The general mortality, under the antitoxin treatment, was 19.5 per cent.; a reduction of 10 on the percentage mortality of the cases treated in the hospitals of the Metropolitan Asylums Board in 1894. If 15 fatal cases, in which death took place within twenty-four hours of the first injection, be deducted, the mortality falls to 15.6 per cent.; which is very little more than half the mortality during 1894 under other forms of treatment. "The lessened mortality is especially noticeable in the earlier years of life, the percentage mortality of children under five being 26.3, as opposed to 47.4. In the next period of five years, the percentage of mortality is 16.0, as opposed to 26.0; whilst after ten years of age the difference in the mortality is slight.[21] [21] After childhood, the disease is much less fatal. "Laryngeal diphtheria is admittedly the most dangerous form. The laryngeal cases have a percentage mortality of 23.6 in the antitoxin, as compared with 66.0 in the non-antitoxin series. In the cases in which laryngeal symptoms are so severe as to necessitate tracheotomy, the saving of life by the use of antitoxin is very marked, the mortality being reduced one-half, to 36.0 as opposed to 71.6 per cent. "The strongest evidence of the value of the antitoxin treatment is that, in addition to reducing the general mortality by one-third, the duration of life in the fatal cases is decidedly prolonged. These two facts taken together conclusively prove the beneficial effects of the antitoxin treatment. "The incidence of paralysis is greater in the antitoxin than in the control series. This increased number is partly explained by the lessened mortality, and partly by the longer duration of life in the fatal cases affording time for the development of paralytic symptoms. The percentage mortality of those who had some form or other of paralysis is lower in the antitoxin than in the control series; so that, notwithstanding the apparent greater risk of paralysis supervening, the probability of final recovery is greater.