CHAPTER VI. 



TYPHOID. 



Discovery' and morphology of the organism — Method of staining — 

 Growth on media — Occurrence and distribution of enteric fever — Con- 

 veyance of typhoid by water, milk, dust, shell-fish, vegetables, etc. — 

 Pathogenesis — The bacteriological diagnosis of enteric fever — The 

 serum treatment of typhoid — LofHer's and Abel's researches on the 

 immunising substance in blood serum — Practical disinfection. 



The bacillus of typhoid or enteric fever {Bacillus typhi ahclo- 

 minalis) was first described in the year 1883 by Bberth, who 

 stained it in sections of the intestine of patients who had 

 died of typhoid ; in the following year Gaff ky obtained pure 

 cultures of the organism, which is now known as the Eberth- 

 Gaffky bacillus. 



The bacillus is 2*5 to 4*0 /^ long by 0"5 fi thick, which is 

 somewhat shorter and thicker than the tubercle bacillus. 



The Eberth-Gaffky bacillus is not killed by drying, nor 

 by exposure to a low temperature. Its thermal death-point 

 is 55° C. According to most observers, it does not form 

 spores. Like all the pathogenic organisms, it is preju- 

 dicially affected by light, diffused daylight being sufficient 

 to prevent its development, while direct sunlight is fatal in 

 five hours. The organism grows equally well both under 

 aerobic and anaerobic conditions. The microscopic appear- 

 ance alone is not enough to distinguish it from several 

 other organisms ; in fact, it is not uncommon to find some 



