394 BACTERIA IN INFECTIOUS DISEASES. 



Figs. 3 and 6, Plate XI., the bacillus is seen very 

 indistinctly; but a close inspection of these figures 

 will show a single bacillus containing spores in 

 Fig. 6 ; and in Fig. 3 groups of two contained 

 in an epithelioid cell, the outlines of which can 

 barely be distinguished. Under the microscope 

 these bacilli, which had been stained with fuchsih 

 by Ehrlich's method, were beautifully shown as 

 bright-colored rods, which contrasted strongly in 

 appearance with the decolorized micrococci and 

 putrefactive bacteria in the same specimen. But 

 after a considerable number of trials, no better 

 photographic result could be obtained than that 

 here seen. 



The fact that the tubercle bacillus has not inva- 

 riably been found by competent observers in recent 

 tubercles, and, also, that numerous investigators 

 claim to have produced tuberculosis in susceptible 

 animals by inoculating them with non-tubercular 

 material, must make us unusually exacting as re- 

 gards the experimental evidence furnished by 

 inoculations with pure cultures. The writer has 

 already indicated his reasons for thinking that a 

 series of cultures made upon the surface of a solid 

 culture-medium is less satisfactory, as regards the 

 exclusion of the original material, than where a 

 fluid culture-medium is employed, which is per- 

 vaded throughout by the organism under cultiva- 

 tion. (See p. 311.) 



The force of this criticism will be more fully 

 appreciated when it is remembered that Koch 



