1 70 BACTERIA 



points. It also grows characteristically in Endo and the Drigalski 

 and Conradi media. In sugar media no gas is formed but there 

 is acidification in dextrose, galactose, mannit, maltose, xylose and 

 levulose. The addition of sterile bile to culture medium, 10-50 

 percent, increases the chance of isolating the germ in blood, faeces 

 or urine cultures; it acts by inhibiting other organisms and by 

 supplying salts favorable to the typhoid bacillus. 



Invasion of Body. This organism generally invades the body 

 by way of the alimentary tract, in food and water. Flies may 

 infect milk and other foods. Oysters may become infected and 

 cause disease. Personal contact, by hand to hand for example, 

 is a very potent method of transmission. 



Pathogenesis. It is certainly the cause of typhoid fever. 

 During the attack the germs circulate in the blood-stream during 

 the entire fastigium but are obtained with ease only in the first 

 two weeks. They are constantly in the faeces for varying periods 

 even after clinical recovery and may be frequently found in the 

 urine. Rose spots also contain them. Also found in the spleen 

 and gall-bladder. It produces well-marked histological changes 

 in the lymphoid structures, particularly in Peyer's patches, 

 solitary foUicles, and other lymph-glands. There is, according 

 to Mallory, a massive endothelial proliferation in the lymph- 

 glands. This causes occlusion of the lymph-vessels, and is fol- 

 lowed by necrosis (ulceration) of the Peyer's patches. The in- 

 tense phagocytic action of the fixed lymphatic cells in the glands 

 is manifest toward the red blood cells, which are devoured in 

 great , numbers. The toxin causes degeneration of other organs, 

 particularly in the liver. Bacilli are found in the spleen and 

 blood. The rose-colored spots are found to be full of them. 

 The disease is certainly not a merely localized infection of the 

 lymph structures, but is a bacteriaemia. There is often a mixed 

 infection in which streptococcus pyogenes in the blood plays an 

 active role. In the necrosis of bone and in subphrenic abscess 

 the typhoid bacilli may act as a pus former. Commonly it 



