A Virus Disease of Swiss Mice Transmissible by Intranasal Inoculation

Mice have been extensively employed in the study of the virus of human influenza since the discovery by Andrewes, Laidlaw, and Smith,1 and by Francis2 that these animals are susceptible to intranasal inoculation of ferret-passed virus. Francis3 has recently shown that influenza virus cultivated in the chorio-allantoic membrane of the developing chick embryo is pathogenic for mice and does not require ferret passage to raise its virulence. Many of the immunological studies of influenza virus have been made by means of protection tests using mice as test animals. It is obvious, therefore, that if the virus of the common cold could be made virulent for mice, a similar and valuable immunological study of this virus could be made.After a number of preliminary failures in attempts to infect mice by intranasal inoculation of the virus of common cold, we began, during the summer of 1936, to use virus for inoculation which was being cultivated in the chorio-allantoic membrane of the chick embryo. By this means, wi...