This book was reviewed by two persons interested in virology. All but the last paragraph was mutually agreed on. One reviewer insisted on the addition of the last paragraph despite the fact that it might be considered superfluous and not apropos.
In all fields of work where vast numbers of facts are accumulated, one must stop occasionally and try to interpret and to integrate them with a possible working hypothesis in view. The facts, when brought together into a satisfactory relationship, may point the way toward further progress. It does not matter whether the hypothesis is correct, so long as it is responsible for additional knowledge, which eventually may even render the original hypothesis untenable.
Burnet indulges in speculations about origins and changes in viruses and virus diseases from a biologic angle. He admittedly has taken the privilege and license of a lecturer and has gone somewhat beyond what would