DISTRIBUTION OF BACILLI 429 



a streptococcus. If oil or melted butter is added to the bouillon 

 so that drops float on the surface, then a striking mode of growth 

 may result, to which the term " stalactite " has been applied. 

 This consists in the growth starting from the under surface of 

 the fat globules and extending downwards in the form of 

 pendulous, string-like masses. These masses are exceedingly 

 delicate, and readily break off on the slightest shaking of the 

 flask ; accordingly during their formation the culture must be 

 kept absolutely at rest. This manner of growth constitutes an 

 important but not absolutely specific character of the organism ; 

 unfortunately it is not supplied by all races of the organism, and 

 varies from time to time with the same race. The organism 

 flourishes best in an abundant supply of oxygen ; in strictly 

 anaerobic conditions almost no growth takes place. 



The organism in its powers of resistance corresponds with 

 other spore-free bacilli, and is readily killed by heat, an exposure 

 for an hour at 58 C. being fatal. On the other hand it has 

 remarkable powers of resistance against cold ; it has been exposed 

 to a temperature several degrees below freezing-point without 

 being killed. Experiments on the effects of drying have given 

 somewhat diverse results, but as a rule the organism has been 

 found to be dead after being dried for from six to eight days, 

 though sometimes it has survived the process for a longer period ; 

 exposure to direct sunlight for three or four hours kills it. When 

 cultivated outside the body the organism often loses its virulence, 

 but some races remain virulent in cultures for a long period of 

 time. 



Anatomical Changes and Distribution of Bacilli. The 

 disease occurs in several forms, the bubonic and the pulmonary 

 being the best recognised ; to these may be added the septiccemic. 

 The most striking feature in the bubonic form is the affection of 

 the lymphatic glands, which undergo intense inflammatory 

 swelling, attended with haemorrhage, and generally ending in 

 a greater or less degree of necrotic softening if the patient lives 

 long enough. The connective tissue around the glands is 

 similarly affected. The bubo is thus usually formed by a 

 collection of enlarged glands fused by the inflammatory swelling. 

 True suppuration is rare. Usually one group of glands is 

 affected first, constituting the primary bubo in the great 

 majority the inguinal or the axillary glands and afterwards 

 other groups may become involved, though to a much less 

 extent. Along with these changes there is great swelling of 

 the spleen, and often intense cloudy swelling of the cells of the 

 kidneys, liver, and other organs. There may also occur secondary 



