Biologists, zoologists, physicians, and scientists who work with small animals have found Wirtschafter's Genesis of the Rat Skeleton, published in 1957, an invaluable guide in research in rats that has any connection with growth, nutrition, and development. Charles C Thomas and Sons have now brought out Wirtschafter's companion study of the genesis of the mouse skeleton. These two volumes, representing years of arduous work, are a splendid tribute to the diligence, the imagination, and the persistence of Wirtschafter. Students of human growth and development regret that there is no exact companion volume for man, though Todd's extensive radiologic studies of postnatal skeletal growth have established norms in this area.
One of the vexing problems all investigators encounter in experiments in which by one means or another they induce disease is to separate effects which are definitely pathological from variations which may be accepted as being within the range of normal.