640 MICROBIOLOGY OF THE DISEASES OF MAN AND ANIMALS. 



fully developed after a short incubation period. Very large dosage, 

 however, may have the desired effect. In prophylaxis the antitoxic 

 srrum is widely and successfully used in all suspicious cases, and in 

 Fourth of July injuries in particular. 



TYPHOID FEVER.* 

 Bacillus typhosus. 



Typhoid fever is one of the most widespread of bacterial diseases 

 and is found endemic in practically all the countries of the world. 

 Epidemics frequently occur because of the infection of some local 

 public utility related to food or drink, particularly water or milk. 



Typhoid fever occurs naturally only in man. Intraperitoneal inoc- 

 ulation of susceptible animals may result in death with acute peritonitis, 

 but lesions are in no way specific and can be produced by the colon 

 bacillus. 



The period of incubation varies ordinarily from five to twenty-one 

 days, with an average of fourteen days. 



The first week of the disease in man begins with a train of rather 

 indefinite symptoms such as headache, loss of appetite, digestive disturb- 

 ances, lassitude, and sleeplessness. Nose bleed is a peculiar and rather 

 constant feature. The temperature and pulse gradually rise until by 

 the end of five to seven days the former has become high, 103 F. to 104 F. 

 and constant. The temperature continues thus through the second 

 week during which a gradual stupor and occasional delirium, diarrhoea, 

 and enlargement of the spleen occur. The pulse is often dicrotic and 

 there is a rash consisting of isolated flattened rose-colored macules or spots 

 which may be few or numerous and occur in successive crops. During 

 the third week in mild cases these symptoms gradually subside. In 

 severer forms no abatement is shown and complications are liable to 

 occur. The fourth week shows beginning convalescence in the typical 

 case. 



The characteristic pathological findings are swelling and ulceration 

 of the lymphoid structures of the lower part of the small intestine best 

 seen in the Peyer's patches of the ileum just above the ileo-cecal valve. 

 The mesenteric glands and spleen are hyperaemic. Parenchymatous 

 degenerations more or less severe may be found in other organs. The 



* Prepared by Edward Fidlar. 



