

228 TUBER C UL OS IS. 



the tissues. They are straight or slightly curved, and are 

 of uniform thickness, or may show slight swelling at their 

 extremities. When stained they appear uniformly coloured, 

 -/-. or ma y present small 



x" L^ \ , uncoloured spots 



\ fy along their course, 



t *\ v^^ r"* with darkly-stained 

 ^j^J* parts between. In 

 x ^V* |Vx *Y t ^ ie case f the 

 , ^CV U~ ' ^ tubercle bacillus, as 



-y t -< ^ .i of many other or- 



-| N 7 ) V^c ~~ ^ ganisms, a consider- 



y -. *~- ^.' ^""""v ** able amount of 



l*/& . discussion has taken 



\ S^ place as to the oc- 



V (^ currence of spores. 



/ In such a minute or- 



FIG. 62. Tubercle bacilli, from a pure ganism it IS extremely 

 culture on glycerine agar. difficult to recognise 



* Iooa the exact characters 



of the unstained points. Accordingly, we find that some 

 consider these to be spores, while others find that it 

 is impossible to stain them by any means whatever, and 

 consider that they are really of the nature of vacuoles. 

 Against their being spores is also the fact that many occur 

 in one bacillus. Others again hold that some of the con- 

 densed and highly-stained particles are spores. It is 

 impossible to speak dogmatically on the question at 

 present. We can only say that the younger bacilli stain 

 uniformly, and that in the older forms inequality in staining 

 is met with, but it has not been definitely proved that this 

 always indicates spore formation. 



The bacilli in the tissues occur scattered irregularly or 

 in little masses. They are usually single, or two are 

 attached end to end and often form in such a case an 

 obtuse angle. True chains are not formed, but occasionally 

 short filaments are met with. In cultures the bacilli form 

 masses in which the rods are closely applied to one another 



