after more than two weeks' incubation. Three of our subcultures made during the third and fourth weeks of incubation showed for the first time a growth of the bovine variety. Differences in carbon dioxide requirements must be remembered and duplicate cultures made, one being incubated in air and the other in an atmosphere with an increased carbon dioxide tension. This may be obtained by a method such as described by Fitch 27 or by the addition of an acid to a carbonate held in a small container in a museum jar.Best results are obtained with from 5 to 10 per cent carbon dioxide by volume.All organisms isolated should be preserved and given careful study. If this is not practicable, they should be sent to a laboratory, where investigators are conducting these particular bactériologie studies. GENERAL COMMENT Undulant fever has been termed a disease of the future, but the rapidly increasing recognition of cases makes it a problem demanding immediate attention. When any new condition involving the public health thus suddenly presents itself, there is always a danger of making regrettable errors, particularly in legislation concerning it. In undulant fever, due caution in the interpretation of the observations should largely elim¬ inate this danger. A conservative attitude is justified, since it appears obvious that the disease is not a new one but one newly recognized. Deaths are very few, serious sequelae are infrequent and acute suffering is unusual, but there is now occurring an undetermined and probably severe economic loss. In preventing this, the livestock and dairy industry will apparently be concerned, and a prematurely attempted eradication of contagious abortion would prove both ineffective and disastrous. Control measures will be carried out by public demand on the basis of the expressed opinions of physicians and the recommendations of health officials. In many respects the knowledge of undulant fever is very inadequate, and one cannot wisely at this time make hasty conclusions or incriminating state¬ ments. Much economic waste and even impairment of human health (through a decreased consumption of milk) may be avoided if we are content to study care¬ fully and quietly and then act wisely. SUMMARY 1. The characteristics of Brucella melitensis organ¬ isms have only recently been fully described.
A classification of strains isolated from humanbeings cannot now be regarded as a reliable index of the importance of the different varieties as a cause of human disease.3. A special effort should be made to obtain a detailed postmortem study in all fatal cases of undulant fever.4. The pathologic lesions and clinical signs of Brucella melitensis infections in animals show a definite correlation.5. The epidemiologie data, based on the reports of more than a thousand recent cases of undulant fever in the United States, indicate that cattle and hogs with contagious abortion are the source of these infections. 6. Macroscopic agglutination tests on patients with febrile illnesses of undetermined etiology should be made ...
