BACILLUS TYPHI ABDOMINALIS 171 



In Grape, Milk, and Cane Sugar Media no fermentation takes place, 

 and according to Hellstrom, in media containing 4 per cent, milk sugar 

 and 1 to 4 per cent, peptone, inoculated with the typhus bacillus, and 

 kept at 37 C. for twenty-four hours, the colonies developing are much 

 smaller than those of the coli commune under similar conditions. 



On Halzs Potato Gelatine (for preparation of same, see Technique, 

 79) the growth of this bacillus and the coli commune is more 

 pronounced than that of other ordinary bacteria. To this medium 

 Eisner added 1 per cent, iodide of potassium (see Technique, 79). 

 On this medium the coli commune grows more energetically than the 

 typhoid bacillus, exhibiting dark brown colonies in forty-eight hours, 

 whereas the colonies of the typhoid bacillus appear as clear, watery drops. 

 This growth is however not absolutely constant, further identification 

 with other culture methods being necessary. 



Vitality. In sterilized water the typhoid bacilli live as long as 

 three months, and increase in numbers at first ; in ordinary water they 

 are destroyed by the concurrence of the ordinary water bacteria in about 

 fourteen days ; in running water this takes place more quickly. Under 

 favourable circumstances, protected from light and drying, they live a 

 long time. In faeces they appear to live three months or more, depend- 

 ing upon the number of putrefactive organisms present. They can 

 withstand cold very well ; freezing and thawing two or three times does 

 them no harm. They are not so resistant to heat, being destroyed with 

 certainty in ten minutes at 60 C., and in a shorter time at higher 

 temperatures. 



Specific Reactions. 1. The indol reaction does not exist except by 

 Peckham's method of repeated transplantation at short intervals into 

 either Dunham's peptone solution, or freshly prepared alkali tryptone 

 solution. Chantemasse has also seen a red colour produced in old 

 cultures with the addition of the indol reagents. 



2. Produces no formation of gas in the culture media. This test is 

 made with grape sugar bouillon and a fermentation tube at 37 C. 



3. On lactose-litmus-agar, pale blue colonies develop with no red- 

 dening of the surrounding medium ; but if glucose is used instead of 

 lactose, both the colonies and the surrounding medium become red. 



4. Gruber's Reaction. When immune serum is added to a bouillon 

 culture of the suspected bacillus in the proportion of one to forty, in 

 twenty-four hours, if the organism is the typhoid bacillus, appearances of 

 agglutination are evident ; the bacteria form granular masses at the 

 bottom of the test-tube, while the upper portions of the medium remain 

 clear. These phenomena can be further examined microscopically, and 

 the agglutination and loss of motility of the organisms confirmed. 



Widal's Reaction. The following is the method of making the test : 

 A drop of blood is taken from the ear or finger of the suspected typhoid 



