Discussion of Papers on Measles Virus

Francis L. Black, Ph.D., Yale University School of Medicine, New Haven, Conn.: Dr. McCarthy has given us an excellent review of what is known of strain variation in measles, and I would like to take this opportunity to compliment him on his helpful presentation. Without in any way disagreeing with Dr. McCarthy's analysis of the production of different types of cytopathic effects (CPE) under comparable conditions as manifestations of differences in virus strain, it might be worth noting again the importance of the cell in determining the outcome. The cytopathic changes which we observe are changes in the cell as well as on the virus. While the strains developed by Oddo and his co-workers1gave a consistent type of CPE in 3 types of culture, other examples have been quoted, notably the work of Dr. Milovanovic, in which a virus preparation gave distinctly different effects in different cultures. It