364 TYPHOID FEVEK 



have usually been found to be dead after three weeks 

 (Frankland). 



Biological Reactions. — The growth of the typhoid bacillus 

 on certain special media facilitates its being differentiated from 

 the b. coli and the other members of the coli-typhoid group; 

 its reactions in these media are largely negative. (See Table, 

 p. 396). 



The tests with sugars are important. The typhoid bacillus 

 produces acid without gas in maltose, laevulose, glucose, and 

 mannite, but originates no change in lactose, cane-sugar, or 

 dulcite ; in the last, however, acid formation may appear after 

 some weeks. Further, there is no curdling of milk, although in 

 litmus milk slight acid production occurs ; in a time varying 

 from a few days to a month the acid change may be succeeded 

 by alkali production. Under ordinary circumstances, the typhoid 

 bacillus is incapable of producing indol in peptone-salt solution, 

 and does not alter neutral-red in lactose bouillon. 



A great many special tests were formerly in use in differ- 

 entiating the b. typhosus from the b. coli. The use of these 

 is not now so necessary, but the following may be described : — 



The Media of Oapaldi and Proskauer. — The first of these ("No. 1 ") is 

 a medium free of albumin, in which b. coli grows well and freely produces 

 acid, while the typhoid bacillus hardly grows at al), and certainly will 

 produce no change in the reaction. Its composition is as follows : 

 asparagin '2 parts, mannite "2, sqdium chloride "02, magnesium sulphate 

 '01, calcium chloride "02, potassium monophosphate "2, distilled water 

 to 100 parts. The second medium ("No. 2") contains albumin, and 

 in it the b. coli produces no acid, while the typhoid bacillus grows well 

 and produces an acid reaction. It consists of Witte's peptone 2 parts, 

 mannite "1, distilled water to 100 parts. After the constituents of each 

 medium are mixed and dissolved, it is steamed for one and a half hours 

 and then made neutral to litmus — the first medium, being usually 

 naturally acid — by sodium hydrate, the second, being usually alkaline, by 

 citric acid. The medium is then filtered, filled into tubes containing 

 5 c. c. , and these are sterilised. After incubation for twenty hours the 

 reaction of the infected medium is tested by adding litmus. 



The identification of the, typhoid bacillus is best facilitated 

 by means of agglutination reactions which will be treated of 

 later (p. 390). 



The Pathology of Typhoid Fever. — The inflammation and 

 ulceration in the Peyer's patches and solitary glands of the 

 intestine are the central features. In the early stage there is 

 an acute inflammatory condition, attended with extensive 

 leucocytic emigration and sometimes with small haemorrhages. 

 At this period the typhoid bacilli are most numerous in the 

 patches, groups being easily found between the cells. The 



