of toxin being given, the remaining two doses being commonly tolerated without further reaction.

In all the experiments here recorded, the unmodified toxin as prepared in the City laboratories has been used for immunising purposes. Severe reactions were eliminated by the employment of three graduated doses of the toxin injected at weekly intervals, the first injection consisting of 500 skin doses, the second of 1,000 and the third of 3,000 skin doses. The injections are made subcutaneously into the upper arm near the insertion of the deltoid muscle. It was observed that in children under six years of age the reaction produced by such injections was negligible. It was also found that immunity to scarlet fever, as judged by a negative Dick reaction, after immunisation, developed much more rapidly than the immunity to diphtheria followed on toxoid-antitoxin injections. Immunity to scarlet fever commonly appears two weeks after the third injection, whereas in diphtheria the period, as already stated, varies from six weeks to six months.

(j) Active immunisation against Scarlet Fever of Staff at City Hospital.-Since 1st June, 1925, the nursing staff of the City Hospital have been actively protected against scarlet fever before being admitted for duty to the scarlet fever wards. Of 122 nurses Dick-tested, 32, or 26-2 per cent., and of 29 maids Dick-tested, 7, or 24.1 per cent., were found Dick-positive.

The 32 susceptible nurses received a first series of three immunising injections at intervals of a week, and on retesting them, three weeks after the third injection, 29 were found to be Dick-negative, 2 were definitely Dick-positive, and 1 faintly positive. These three last-mentioned nurses received a second series of immunising injections, and on retesting three weeks later all were found to have become Dick-negative. Of the 7 maids who were found to be susceptible to scarlet fever, 6 received one series of three immunising injections at intervals of a week, and all 6 were found to be Dick-negative on retesting one month later. The remaining maid who had been found to be Dick-positive received only one injection of 500 skin doses of toxin, as 24 hours after this injection she developed a condition indistinguishable from scarlet fever. After her illness she was retested and found to be Dick-negative. On retesting these nurses and maids in September, 1926, all of them were Dicknegative.

(k) Effect of Active Immunisation in Preventing Scarlet Fever in the Staff of the City Hospital.-Among the 32 nurses and 6 maids who were found to be Dick-positive and were not put on duty in the scarlet fever wards until they had been immunised and become Dick-negative, there has been no case of scarlet fever.

It was, however, noted that coincident with the disappearance of scarlet fever in the immunised nursing staff of the City Hospital, there had been a notable increase in the incidence of streptococcal tonsillitis among those immunised nurses. Thus

in the decennium of 1916-1925 there was an annual average of 11 cases of tonsillitis in the 95 nurses comprising the nursing staff, or a case incidence of 11.6 per cent., whereas in the year October, 1925, to September, 1926, the number of cases was 25, or 26.3 per cent. Before immunisation was practised an annual average of 9 cases, or 9.5 per cent., contracted scarlet fever in the City Hospital, and, if this number is subtracted from the 25 cases of tonsillitis, it leaves an average annual number of 16 nurses suffering from tonsillitis, or 16.8 per cent. It has been found that the streptococci obtained from these cases of tonsillitis commonly fall into one or other of the serological groups of scarlatinal streptococci, and it would appear that the immunised nurses, while protected against scarlet fever, are not protected against tonsillitis due to the scarlatinal streptococci.

(1) Active Immunisation against Scarlet Fever of Patients admitted to Hospital with Diphtheria.-Advantage was taken of the admission of cases of scarlet fever to the City Hospital to test all such patients for susceptibility to diphtheria, and to provide a first series of diphtheria toxoid-antitoxin injections to those found to be susceptible. In the same way, on the admission of all cases of diphtheria to hospital, sanction is obtained to provide active immunisation against scarlet fever for these patients, and all such patients are Dick-tested on admission. It has not been found practicable, however, to proceed with the active immunisation of the Dick-positive reactors while in hospital, owing to the fact that, as already indicated, the scarlatina prophylactic produces an erythema in 3 per cent. of the individuals immunised. The presence of this erythema has been found to present a serious difficulty in the differential diagnosis of the rash due to the injections, and of the rash of scarlet fever. It has accordingly been found preferable to arrange for the active immunisation of the Dick-positive reactors among the diphtheria patients after they are discharged from hospital.

(m) Active Immunisation of School Children against Scarlet Fever. After five months' experience of the apparently effective protection provided to nurses in the City Hospital by active immunisation, it was considered that the evidence was sufficient to justify a wider application of this preventive procedure. Accordingly, in November, 1925, sanction was obtained from the Education Authority to provide active immunisation against scarlet fever to school children. In all, 303 school children have, to the end of September, 1926, received a first series of immunising injections of the scarlatinal prophylactic. Of these, 257 were retested within four months of receiving the first series of injections, and 194 of them, or 75.6 per cent., were found to be protected, as indicated by a negative Dick reaction. None of the 194 school children thus protected has contracted scarlet fever, though the disease has been rife in the schools. One of the children who received a first series of injections, and who had not yet been retested, developed scarlet fever two months after receiving the injection.

(n) Prevention of Return Cases of Scarlet Fever. The problem of the return case of scarlet fever has apparently been insoluble until active immunisation against the disease was made available. Since the beginning of hospital isolation of scarlet fever, patients have been discharged from hospital apparently well, and, within a few days to a month of their return home, have originated fresh cases of the disease. It is true that many of these apparently clean cases of scarlet fever that originated return cases were, on later examination, found to be suffering from discharges of one kind or another, but it has been the experience of every one associated with fever hospital practice that on occasion the convalescent patient, who left hospital without any discharge whatsoever and apparently free from all infection, has originated fresh cases.

It occurred to the authorities in Aberdeen that the new active immunising device against scarlet fever might profitably be employed to protect all the susceptible members of the families to which scarlet fever convalescents were discharged from hospital. Accordingly steps were taken to have every family, from which a case of scarlet fever had been removed to hospital, visited within twenty-four hours, and to have all the remaining members of the family Dick-tested. The results of these Dick tests are read twelve hours later, and all positive reactors are given a first immunising injection of 500 skin-test doses of scarlatinal streptococcus toxin, five days later a second injection of 1,000 skin test doses, and five days after the second. injection a third injection of 3,000 skin test doses are given. Within 14 days of the third injection (that is 24 days after the case of scarlet fever has been removed to hospital), these susceptible contacts are found, in the great majority of cases, to be immune to scarlet fever, as judged by a negative Dick reaction. Accordingly, when the scarlet fever patient is discharged from hospital, he returns home to a family, the susceptible members of which have all been immunised against scarlet fever. Up to the end of September, 1926, some 470 families were visited, and arrangements were made with 134 of the families to have the susceptibility tests and necessary immunising injections carried out by the family doctor. In 84 out of the 470 families the patient admitted to hospital was an only child. The members of the remaining 252 have been tested and immunised under the supervision of the Health Department. The results of the Dick tests, as already recorded, indicate that it is unnecessary to Dick-test children under six years of age, since 964 per cent. of such children are Dick-positive. Accordingly it has been possible actively to immunise without preliminary testing 277 children in the 252 families. An additional 233 children over six years of age in these families were Dick-tested; of these 154, or 661 per cent., were found positive, and these positive reactors were also actively immunised against scarlet fever. It is interesting to note that, up to the time of reporting (September, 1926) only one return case of scarlet fever has occurred

in the 252 families which have been thus protected. During the quinquennium 1921-25, an annual average of 439 cases of scarlet fever was notified, an annual average of 369 cases was admitted to hospital, and these hospital admissions on discharge caused an annual average of 22 return cases, or 5.9 per cent., of admissions. During the period August 1925 to September 1926, 1,027 cases of scarlet fever have been notified; 661 cases from non-immunised households have been admitted to hospital where they received serum treatment; and these on discharge have caused 13 return cases, or 20 per cent. of admissions; while 252 cases from immunised households have been admitted to hospital where they received serum treatment, and these on discharge have caused 1 return case, or 0.4 per cent. of admissions. The contrast, therefore, is that among the non-immunised families from 20 per cent. to 5.9 per cent. of scarlet fever admissions have on discharge caused return cases, whereas the discharge of 252 cases to immunised households has resulted in the production of 0.4 per cent. of return cases.

(o) Control of Epidemic Prevalence of Scarlet Fever by Active Immunisation.-The results already recorded of the Dick test for susceptibility of actively immunising susceptible individuals, and of retesting these individuals, have indicated that in about 95 per cent. of cases the Dick-positive reactors become Dick-negative a fortnight after the third immunising injection, although this Dick-negative reaction may not be permanent. Immunity to scarlet fever induced by streptococcus toxin develops much more rapidly than the immunity to diphtheria induced by diphtheria toxoid-antitoxin injections, which takes from six weeks to six months to develop. Immunising injections against scarlet fever when made widely available would therefore seem to provide a hopeful prospect of checking immediately the epidemic prevalence of scarlet fever as contrasted with the known failure of diphtheria toxoid-antitoxin injections to control immediately epidemics of diphtheria. In the community immunising campaign which is at present being undertaken in Aberdeen, epidemic control of scarlet fever is being attempted, but it is obvious that it will be a considerable time before reliable statistics of the results are available for publication.

11. Glasgow.-A considerable amount of research work is being carried out in all the City's fever hospitals in regard to the Dick test. The test is also offered to probationer nurses in one of the fever hospitals. But active immunisation with scarlet toxin has not been undertaken so far at any of the hospitals.

12. Edinburgh.-The Dick test has been made use of in 833 cases in various institutions in Edinburgh for the purpose of controlling epidemics of scarlet fever. Where circumstances have permitted, children susceptible to scarlet fever, as indicated by a positive Dick test, have been isolated and passively protected by the injection of small amounts of scarlet fever antitoxin.

In the City Hospital, Colinton Mains, Dick-testing has been carried out on a considerable scale, and 102 persons, including 51 of staff, have been immunised against scarlet fever. Dr. Benson, Medical Superintendent of the City Hospital, Colinton Mains, Edinburgh, and Dr. G. W. Simpson, the Senior Resident Medical Officer at the same hospital, have published the results of their work in the immunisation of some of the nursing staff during 1926 in the Lancet of February 5th, 1927. Summarising their results they found that of 42 originally Dick-positive nurses, 37 (88.1 per cent.) were rendered Dick-negative with specific scarlet fever toxin within varying periods of time up to eight months from the completion of the primary course of protective injections.

The conclusions arrived at by the authors are as follows:(a) By the injection, at intervals of from five to fourteen days, of gradually increasing doses of scarlet fever toxin, it is possible to render the majority of Dick-positive reactors Dick-negative; (b) provided the dosage is carefully graded, this can be accomplished without the development of any unpleasant or permanent ill-effects; (c) whilst active immunity can be attained by the injection of relatively small doses of toxin, its duration in cases originally strongly Dick-positive is only a matter of months; (d) should a more lasting immunity be desired in marked Dickpositive reactors, much larger injections of toxin than hitherto employed are apparently necessary.

13. Dundee. The rule is to subject to the Dick test and to immunise as many as possible of the patients admitted to King's Cross Hospital, except those suffering from scarlet fever. In this way during 1926 the number of patients Dick-tested and immunised by a series of three injections of toxin was 88, of whom 32 were under five years, 42 between five and fifteen years, and 14 over fifteen years of age.

14. Aberdeen County.-Of 5,089 Dick tests, 2,988 were read as positive and 2,101 as negative. Of those read as positive 53 received four injections of scarlet fever toxin, 456 received three, 36 received two injections, and 13 received one injection.

Five cases immunised against scarlet fever subsequently developed the disease. Of these one case developed a month after the third dose; one, three months and eleven days; two, six months, and one about ten months after the third dose.

15. Lanarkshire.-In the County of Lanark, Dr. Patterson, the Medical Officer of Health, says that the staff at the County Hospital in Motherwell are all Schick and Dick-tested, and those found susceptible are immunised against diphtheria and scarlet fever.

Scarlet fever patients are as far as possible Schick-tested and the susceptibles immunised against diphtheria. Diphtheria patients are Dick-tested and the susceptibles immunised against scarlet fever, as far as possible without prolonging their residence in hospital. Further developments of this work are at present