1. A virological study of 15 children below the age of 12 years, suffering from measles diagnosed by the senior medical staff of the City Fever Hospital in Edinburgh was undertaken. The measles virus was isolated from the blood of five, cases, from throat swabs of four, from the urine of one, and from the lung of a fatal case of measles meningo- encephalitis. Neutralisation and complement fixation methods were used to estimate the antibody levels to both viruses. The titres of complement fixing antibodies to measles ranged from 1 in 8 to 1 in 512 but those for the distemper virus were appreciably lower varying between 0 and 1 in 32.
2. A somewhat similar study was made on dogs seen in the Small Animal Clinic at the Royal Dick Veterinary College. Virulent strains of the distemper virus were .isolated from the blood and spleen of one adult dog and three puppies found suffering from distemper and later destroyed. Antibody levels were estimated from six dogs in the late stages of infection, -animals which were later destroyed. Complement fixing antibody levels for the distemper virus ranged from 1 in 8 to 1 in 128 but for the measles virus none were higher than 1 in 8.
3. By using a combination of pancreatin and trypsin instead of trypsin alone it was found that the yield of cells for culture from human amniotic membrane was increased at least one and a half fold and that this technique was so satisfactory that it was employed throughout.
4. A study of the cytopathic effects of the measles virus was made in human amnion and human kidney primary tissue cultures and in secondary monkey kidney cell cultures and was extended to include the following human cell lines: - HeLa, HEU -2, and a local strain of foetal lung cells. The measles virus also grew well in primary cultures of ferret kidney producing typical giant cells.
5. A comparative study using various staining methods was made on the morphology of the giant cells, syncytia, and inclusion bodies produced by the two viruses in tissue culture. The measles virus produced the larger syncytia with nucleii scattered evenly throughout while the distemper virus produced a rather large giant cell with a cluster of nuclei at the centre and also with a peripheral ring of nuclei. "Stellate' cells were more numerous in measles cultures than in dis- temper infected cells. Little or no difference in the nature or the site of the inclusion bodies could be made out between the two viruses.
6. The distemper virus could not be adapted to grow in primary cultures of human amnion or secondary monkey kidney cells: nor was it found possible to adapt the virus to grow in cell lines of human origin, e.g. , HeLa, HEf -2, or foetal lung.
7. The distemper virus grew satisfactorily in ferret or dog kidney tissue cultures. Growth of the virus in ferret kidney cells was more rapid and the cytopathic effect more profound when the cultures were incubated at 39 °C instead of 37 °C.
8. A study of the morbid anatomy of the ferret infected with virulent distemper virus was made and included a histopathological comparison of the tissues of normal and diseased animals. The lesions were more severe than those described for measles in man but the giant cells in the lymphoid tissues were practically identical with the Warthin -Finkeldey cells in human tissues.
9. Both measles and distemper viruses were adapted to grow in suckling mice in which host a spastic paralysis and death occurred.
10. An attempt to infect adult and young six week old ferrets with the measles virus failed. Infection, however, was achieved when the virus was injected intra-cerebrally into two -day old suckling ferrets under the influence of cortisone. In one animal the virus was recovered ten weeks after inoculation.
11. When ferrets were immunised with the measles virus they were not protected against a lethal challenge by a virulent strain of the distemper virus. However, there was a slight prolongation of the incubation period.
12. When ferrets were immunised with attenuated distemper virus followed later by an injection of virulent virus they developed high levels of antibodies to distemper but only low levels to the measles virus.
13. The measles virus was found to be able to agglutinate the red blood cells of rhesus monkeys and the serum of convalescent measles patients had a power to inhibit this haemagglutination. The complement fixing, neutralising, and haemagglutination inhibiting properties of sera from measles patients ran parallel.
14. The canine distemper virus was found to possess no haemagglutinating property. Canine sera with high levels of antibody to the distemper virus did not inhibit haemagglutination by the measles virus.
15. A comparison of the serologic findings in measles and distemper was made using a wide variety of immunological techniques including neutralisation tests in animals, eggs and tissue cultures as well as complement fixation and agar gel diffusion. It was apparent in complement fixation and in some neutralisation experiments that a moderate degree of antigenic sharing was present but infection with one virus did little to protect an animal against infection with the other.
16. In agar gel diffusion experiments the measles virus gave three bands of precipitation when it was set up against its homologous serum whereas the distemper virus gave only two. This finding, which was confirmed by immune electrophoresis is interpreted as indicating that the measles virus possesses an antigen not present in the distemper virus. This antigen may possibly be the haemagglutinin.
17. It was found that 5 fluoro-deoxyuridine inhibited the growth of the measles virus in infected HeLa and monkey kdiney cells. Since this substance did not influence the multiplication of the poliomyelitis virus type 1, a known ribo virus, and did inhibit the growth of the vaccina.virus, a known deoxyvirus, it is concluded that the measles viruses contain deoxyribonucleic acid.
18. Further evidence that the measles and distemper viruses may be a deoxyvirus was provided by preparations which had been stained with the fluorescent dye acridine orange. Infected cells, giant cells and syncytia stained with an apple green D.N. A. fluorescence throughout and the red R.N.A. staining property of the normal cell was lost. A similar colouration was seen in the viral inclusions in the nucleus and in the cytoplasm.
19. Electron -microscopical examination of the two viruses by negative staining methods shows them to be almost identical, the only difference between the two being the thicker limiting membrane of the measles virus.
20. Both viruses possess a helical symmetry resembling somewhat that of the Newcastle and mumps viruses.
21. When the particles of both viruses have been disrupted disc like structures as well as the helix are liberated. It is suggested that the discs are capsomeres (sub units) which are attached to a central spiral core of deoxyribonucleic acid and that as they protrude they confer on it a typical "herring bone" appearance.
22. The position of the measles, distemper, rinderpest group of viruses in relation to the herpes group and other viruses is discussed.