The evidence presented supports the hypothesis that the experimental form of anthrax induced by depositing a cloud of single spores on lung epithelium is initiated in the lymphatic regions and not in lung tissue.Proportionately few of the deposited spores reach the lymph glands. The majority remain inactive in so far as induction of disease is concerned. Slowly, however, they seem to go through the first stages of germination but do not multiply and therefore die. This is probably the major factor operative in their disappearance from the lung.Effective prophylactic measures are suggested for dealing with an unimmunized host exposed to anthrax infection by the pulmonary route.

SUMMARY:An agar-diffusion method is described for the titration of Bacillus anthracis immunizing antigen and antibody. It is a sensitive and simple method that can be used for determining antigen concentrations in culture filtrates and for titrating antisera from animals and humans which have been immunized with the antigen. Marked improvements in yields of antigen in a defined medium and a hydrolysed casein + amino acids (Casamino) medium have been achieved with the aid of this assay method.

The production of licheniformin-like antibacterial activity in culture by a single strain of Bacillus licheniformis required neutral or alkaline conditions, conveniently attained by the use of lactate rather than glucose as a source of carbon in a chemically defined medium.When the medium contained initially about 0.0P-0.10 yo nitrogen, supplied as asparagine or as ammonium lactate, and the cultures, harvested after 4-9 days a t 37O, were sterilized by bringing to pH 2.5 and autoclaving, the inhibitory dilution against a test strain of Mycobacterium phlei was 1/160 or greater.Fluid from cultures in a chemically defined medium, containing 0.06 M ammonium lactate and 0.05 M sodium lactate, inhibited the test organism a t a dilution of 1/200-1200 (geometric mean, 530) in 44 consecutive batches of 100-200 1. culture fluid produced by incubation of cultures in shallow layers. The pH value of the harvested fluid was about 9 and the antibiotic material was partly bound by the cells. It was largely freed by adjustment to pH 2.5.When amino-acids were added to the medium either as a mixture of known aminoacids, or as a casein hydrolysate, the maximum titre was attained earlier, but with no significant change in its value. A similar result was obtained with yeast extract added alone or with casein hydrolysate.

A method is described for the production of primary chick embryo cell suspensions that allows the processing of from 200 to several thousand embryos daily at a significantly lower cost than with other methods. Special apparatus enables high yields of cells, free of microbial contamination to be produced under controlled conditions with the minimum of supervision.