I. The influence of age and temperature on the potency of diphtheria antitoxin, by John F. Anderson. II. An organism (Pseudomonas protea) isolated from water, agglutinated by the serum of typhoid fever patients, by W. H. Frost. III. Some considerations on colorimetry, and a new colorimeter, IV. A gas generator, in four forms, for laboratory and technical use, by Norman Roberts | lit.salon