Delayed Hypersensitivity

in agriculture, an application that accounts for approximately 40% of the total production of these agents. It is obviously impossible to give detailed descriptions of the many excellent papers in this volume, but some points may be noted. From a pharmacological viewpoint, the area of structure-activity relationships is particularly well covered in regard to penicillins (K. et al.) and lincomycins (B. J. Magerlein et al.). On reading these papers one is impressed with the increasingly important function of synthetic chemistry in developing new antibiotics with features such as resistance to enzymatic degradation or improved absorption when given orally. The development of potential antiviral agents is currently receiving much attention , and this area is well represented, including descriptions of several suitable assay systems. The section on clinical evaluation, which is the largest one (29 papers), includes such topics as clinical trials of cephalo-sporin derivatives and isoxazolyl penicillins, antibiotic synergism, the incidence of antibiotic resistance, and the use of several antibiotics in premature and neonatal infants and children. There is a list of authors and a very brief subject index. The binding and type appear satisfactory. The present volume is number 4 in a series of research monographs on "Frontiers of Biology," published under the editorship of A. Neuberger (London) and E. L. Tatum (New York). Other volumes deal with microbial models of cancer cells, interferon, biochemical genetics, and human population genetics, all very timely topics. Delayed or cellular hypersensi-tivity is itself a most timely subject for review, because it is concerned with mechanisms basic to transplantation immunity and autoimmunity, both of which have assumed a major role in contemporary medicine. Thus the review presented here has interest not only for investigators concerned with fundamental biological mechanisms but also for surgeons, who would enlarge their facility in transplanting organs, and internists, who seek deeper understanding of pathogenetic processes in many diseases of hitherto unknown origin.