244 MICRO-ORGANISMS AND DISEASE [chap. 



in those of bacillus coli this plate-like expansion is well 

 developed. 



6. Shake cultures in ordinary and in sugar gelatine do 

 not develop gas bubbles, though the gelatine is in all layers 

 pervaded by colonies. 



7. Milk is not curdled by the typhoid bacillus. 



8. Broth is made rapidly turbid, and after some days an 

 imperfect pellicle may make its appearance, but at no time 

 does such broth give the nitroso-indol reaction. The typhoid 

 bacillus grown in milk, broth, or litmus-whey produces less 

 acid than the typical bacillus coli (Petruschki). 



9. On steamed potato, kept after inoculation at 37° C, 

 the growth is a colourless transparent film. 



10. In nutrient gelatine, containing gelatine to the amount 

 of 25 per cent, the difference between bacillus coli and 

 bacillus of typhoid on incubation at 37° C. is very striking; 

 the (fluid) gelatine remains limpid, and its surface is covered 

 with a thick pellicle during the first forty-eight hours in the 

 case of the typical bacillus coli, but is strongly and uniformly 

 turbid in the case of the typhoid bacillus. 



A bacillus which does not conform to all the above 

 points is in my laboratory rejected as typhoid. Whether or 

 not a bacillus which in one or the other of the above 

 points deviates and approaches the bacillus coli is or is not 

 the typhoid bacillus, has or has not originally been derived 

 from the typhoid bacillus, I feel neither inclined to deny nor 

 to affirm — in the present state of our knowledge it would not 

 be justifiable to do so ; but what I maintain is that since the 

 true typhoid bacillus taken from the spleen of a typical 

 typhoid case possesses all and every one of the above charac- 

 ters it is more justifiable to reject as typhoid those which 

 either in the number and character of the flagella, or in the 

 manner of growth in gelatine shake culture, in milk, in broth. 



